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Postal  address:   Visit  address:   Telephone:  

 

Usability  Evaluation  of  a  Production  System  

Development  Framework  

A  Meta-­‐Study  Performed  on  the  Use  of  a  Production  System  

Development  Framework  in  the  Development  of  a  New    

Production  System  at  Xylem  

 

 

 

Fredrik  Arnesson  

Johan  Bengtsson  

 

 

 

 

THESIS  WORK  2012  

PRODUCTION  SYSTEM

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Postal  address:   Visit  address:   Telephone:  

 

Usability  Evaluation  of  a  Production  System  

Development  Framework  

A  Meta-­‐Study  Performed  on  the  Use  of  a  Production  System  

Development  Framework  in  the  Development  of  a  New  

Production  System  at  Xylem

 

 

 

 

Fredrik  Arnesson  

Johan  Bengtsson  

 

This  thesis  work  has  been  carried  out  at  the  School  of  Engineering  at  Jönköping   University  in  the  subject  area  production  development  and  leadership.  The  the-­‐ sis  work  is  a  part  of  the  Master  of  Science  program  Production  System.  

The  students  take  full  responsibility  for  opinions,  conclusions,  and  findings  pre-­‐ sented.  

Examiner:  Glenn  Johansson   Supervisor:  Kristina  Säfsten   Scope:  30  credits  (D-­‐level)   Date:  June  2012  

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Acknowledgements  

We  would  like  to  take  this  opportunity  to  thank  our  supervisor  Kristina  Säfsten   for   her   guidance   and   help   during   the   process   of   writing   this   thesis.   We   would   also  like  to  thank  our  supervisor  at  Xylem  Roger  Sandström  for  providing  us  as-­‐ sistance  throughout  the  performed  work  at  the  company.  Finally,  we  would  like   to  express  our  gratitude  to  all  involved  employees  at  Xylem  for  their  contribu-­‐ tions  and  support.  

 

____________________________________       ____________________________________   Fredrik  Arnesson           Johan  Bengtsson  

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Summary

 

Today’s   competitive   global   market   has   placed   companies   under   great   pressure   and  the  focus  on  production  systems  has  been  more  prominent.  Although  there   are  several  claimed  benefits  with  using  frameworks  in  the  development  of  pro-­‐ duction  systems,  companies  are  reluctant  to  use  these.  Consequently,  a  relevant   question  formulation  is:  Are  frameworks  in  the  development  of  production  sys-­‐ tems  usable?  

The  purpose  with  this  thesis  work  was  therefore  to  evaluate  the  usability  of  pro-­‐ duction   system   development   frameworks   (PSDFs)   in   practice.   In   order   to   achieve  this  purpose,  two  research  questions  were  established:  

RQ1.   How  can  usability  of  frameworks  be  evaluated?  

RQ2.   How  does  the  use  of  a  framework  contribute  to  the  development  of  a  new  

production  system?  

In   order   to   answer   the   posed   research   questions,   Bellgran   and   Säfsten’s   PSDF   was  used  in  the  production  system  development  (PSD)  process  of  a  new  produc-­‐ tion  system  at  Xylem.  Based  on  the  PSD  process,  a  meta-­‐study  was  performed  to   evaluate  the  practical  usability  of  the  PSDF.  Usability  was  defined  and  evaluated   based  on  the  five  usability  terms  learnability,  memorability,  efficiency,  effective-­‐ ness,  and  satisfaction.  

The   result   showed   that   all   the   five   usability   terms   contribute   to   the   usability   evaluation  of  PSDFs.  However,  memorability  was  considered  difficult  to  use  on   only   one   study   since   the   user   has   to   think   a   step   further   and   make   a   qualified   guess  to  answer  if  it  is  possible  to  memorize  a  framework.  Therefore,  it  was  con-­‐ sidered  memorability  is  only  appropriate  to  use  in  a  multiple  study.  

The  results  also  showed  that  Bellgran  and  Säfsten’s  PSDF  contributed  most  in  the   beginning   of   the   PSD   process   by   putting   emphasis   on   the   planning   phase   and   providing  a  structure  to  follow.  Due  to  the  nature  of  a  framework  (i.e.,  to  serve  as   a  guide  for  structures  to  follow),  this  was  not  unexpected.  However,  the  contri-­‐ butions  from  a  structure  or  plan  are  hard  to  exactly  distinguish.  Since  companies   most  often  want  tangible  and  accurate  evidences,  frameworks’  vague  contribu-­‐ tions  are  considered  to  be  a  major  reason  to  why  companies  do  not  use  frame-­‐ works  more  frequently.    

Keywords  

Production  system  development,  Framework,  Usability,  Evaluation,  Meta-­‐Study  

 

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Table  of  Contents  

1.  INTRODUCTION  ...  1  

1.1  BACKGROUND  ...  1  

1.2  PURPOSE  AND  RESEARCH  QUESTIONS  ...  2  

1.3  DELIMITATIONS  ...  2  

1.4  OUTLINE  ...  2  

2.  THEORETICAL  BACKGROUND  ...  4  

2.1  PRODUCTION  SYSTEM  ...  4  

2.1.1  Production  System  Development  ...  5  

2.1.2  Academic  versus  Industrial  Perspective  in  Production  System    Development  6   2.1.3  Production  System  Development  Frameworks  ...  7  

2.2  USABILITY  ...  11  

2.2.1  Definition  and  Description  of  Usability  ...  12  

2.2.2  Measurement  of  Usability  ...  13  

2.2.3  Evaluation  of  Usability  ...  14  

2.2.4  Usability  of  Frameworks  ...  14  

3.  METHOD  ...  16   3.1  RESEARCH  PROCESS  ...  16   3.2  RESEARCH  METHOD  ...  17   3.2.1  Case  Study  ...  17   3.2.2  Meta-­‐Study  ...  17   3.3  DATA  COLLECTION  ...  18  

3.3.1  Primary  Data  Collection  ...  18  

3.3.2  Secondary  Data  Collection  ...  19  

3.4  DATA  ANALYSIS  ...  20  

3.5  QUALITY  OF  DATA  ...  20  

3.5.1  Validity  of  Data  ...  20  

3.5.2  Reliability  of  Data  ...  20  

4.  CASE  DESCRIPTION  ...  22  

4.1  PRODUCTION  SYSTEM  DEVELOPMENT  PROCESS  ...  22  

4.1.1  PLANNING  PHASE  ...  22  

4.1.2  PREPARATION  PHASE  ...  23  

4.1.3  DESIGN  AND  EVALUATION  PHASE  ...  24  

5.  USABILITY  ANALYSIS  OF  PRODUCTION  SYSTEM  DEVELOPMENT  FRAMEWORK  27   5.1  GUIDELINE  FOR  USABILITY  ANALYSIS  ...  27  

5.2  USABILITY  ANALYSIS  OF  BELLGRAN  AND  SÄFSTEN’S  PRODUCTION  SYSTEM  DEVELOPMENT   FRAMEWORK  ...  27  

6.  DISCUSSION  AND  CONCLUSION  ...  33  

6.1  RQ1.  HOW  CAN  USABILITY  OF  FRAMEWORKS  BE  EVALUATED?  ...  33  

6.2  RQ2.  HOW  DOES  THE  USE  OF  A  FRAMEWORK  CONTRIBUTE  TO  THE  DEVELOPMENT  OF  A  NEW   PRODUCTION  SYSTEM?  ...  34  

6.3  THREATS  TO  VALIDITY  AND  RELIABILITY  ...  36  

6.4  SUGGESTIONS  FOR  FURTHER  RESEARCH  ...  36  

7.  REFERENCES  ...  38  

APPENDIX  A:  PLAN  FOR  PRODUCTION  SYSTEM  DEVELOPMENT  ...  I   §  1  INVESTMENT  PLAN  ...  I  

§  2  PROJECT  PLAN  ...  I  

§  3  GUIDELINE  FOR  REQUIREMENT  SPECIFICATION  AND  SYSTEM  SOLUTION  ...  II  

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§  5  ADAPT  THE  WAY  OF  WORKING  TO  THE  SPECIFIC  SITUATION  ...  IV  

APPENDIX  B:  REQUIREMENT  SPECIFICATION  ...  V   §  1  GENERAL  OVERVIEW  ...  V  

§  2  SYSTEM  OVERVIEW  ...  V  

§  3  REQUIREMENTS  AND  OBJECTIVES  ...  X  

§  4  INTERFACES  ...  X  

§  5  CHECKLIST  ...  XI  

APPENDIX  C:  SYSTEM  SOLUTION  ...  XII   §  1  GENERAL  OVERVIEW  ...  XII  

§  2  CONCEPTUAL  SYSTEM  SOLUTION  ...  XII  

§  3  DETAILED  SYSTEM  SOLUTION  ...  XII  

§  4  CONTINUATION  OF  PRODUCTION  SYSTEM  DEVELOPMENT  ...  XX  

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1.  Introduction  

This   chapter   presents   the   background,   purpose,   and   delimitations   of   the   thesis   work.  An  outline  is  also  provided  in  order  to  give  a  general  overview  of  the  report.  

1.1  Background  

Today’s   competitive   global   market   has   placed   companies   under   great   pressure   and  the  focus  on  production  systems  has  been  more  prominent  (Neumann  et  al.,   2002).  Along  with  the  increased  competitive  industrial  situation,  it  is  clear  that   increased   levels   of   output,   efficiency,   effectiveness,   and   quality   can   only   be   achieved   by   developing   new   and   better   production   systems   (Bennett,   1986;   Shang  and  Sueyoshi,  1995).  

Production   system   development   (PSD)   can   take   different   amount   of   time,   all   from  a  couple  of  weeks  to  several  years.  When  something  is  done  infrequently,   like   developing   a   new   production   system,   it   can   aggravate   the   use   of   previous   experience   and   knowledge.   However,   by   using   structured   work   methods   and   trying  to  use  others’  experiences,  one  can  overcome  these  barriers.  A  structure   makes  it  possible  to  focus  on  the  important  parts,  such  as  preparing  and  creating   new  and  accurate  production  systems  (Bellgran  and  Säfsten,  2010).  

Nevertheless   the   claimed   benefits   with   a   structured   approach,   there   are   many   companies  that  tend  to  deal  with  activities  in  development  projects  in  an  ad  hoc   manner  (Bellgran  and  Säfsten,  2010).  Chryssolouris  (1992)  means  the  industrial   practice  is  more  of  a  trial-­‐and-­‐error  approach:  

1. Guess  a  suitable  production  system;  and  

2. Evaluate  the  performance  of  the  system.  If  it  satisfactory,  then  the  design   process  stops,  otherwise  return  to  step  1.  

According   to   Bellgran   and   Säfsten   (2010),   there   are   different   reasons   to   why   companies  do  not  use  a  structured  approach  when  developing  new  production   systems.  Some  of  the  reasons  are  for  example  time  pressure,  low  priority,  fear  of   low  flexibility,  difficulties  to  access  information  with  high  quality,  and  a  lack  of   existing  methods  on  the  market  (Bellgran  and  Säfsten,  2010).  

In  two  company  studies  performed  in  Sweden,  which  focused  on  PSD,  the  intro-­‐ duction  of  new  products  or  product  models  was  the  main  reason  to  why  the  in-­‐ vestigated   companies   were   developing   their   production   systems.   At   the   same   time,  the  companies  saw  a  potential  to  increase  ergonomics  and  work  environ-­‐ ment,  automatize,  get  better  workflow,  and  increase  the  volume  capacity  (Bell-­‐ gran  and  Öhrström,  1995;  Bellgran  1998;  Säfsten  and  Aresu,  2000;  Säfsten,  2002,   see  Bellgran  and  Säfsten,  2010,  pp.  110-­‐111).  

Based  on  empirical  and  theoretical  data,  Bellgran  and  Säfsten  (2010)  have  devel-­‐ oped  a  framework  including  a  structured  way  of  working  in  order  to  assist  the   PSD  process.  The  usefulness  of  this  production  system  development  framework   (PSDF)  has  however  not  been  tested  and  therefore  it  is  interesting  to  investigate   how  usable  PSDFs  really  are.  

First  however,  in  order  to  know  if  something  is  usable  or  not,  it  is  important  to   define  what  usability  really  is.  In  the  context  of  usability,  there  are  different  defi-­‐ nitions   of   the   term   and   considerable   confusion   exists   over   the   term’s   meaning  

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on  the  ISO  9241-­‐11  standard  and  the  usability  consultant  Jakob  Nielsen’s  usabil-­‐ ity   goals:   effectiveness,   efficiency,   satisfaction,   learnability,   and   memorability   (Nielsen,  1993;  ISO  9241-­‐11,  1998).  

An  extensive  literature  review  shows  that  there  is  little  research  made  within  the   production  development  area  in  terms  of  measuring  and  evaluating  usability  of   frameworks.   This   showed   to   be   true   even   in   the   closely   related   product   devel-­‐ opment  area;  an  area  that  is  generally  more  emphasized,  both  in  industry  as  well   in  theory  (Bellgran  and  Säfsten,  2010).  In  terms  of  usability  in  the  product  and   production   development   areas,   it   is   found   that   the   final   results   (i.e.,   the   final   products,  services  etc.)  achieved  from  when  using  frameworks  are  more  in  focus.   In  an  industrial  environment,  it  is  therefore  believed  to  be  relevant  to  investigate   how  usable  PSDFs  are.  

To  be  able  to  evaluate  the  usability  of  a  PSDF,  a  practical  situation  is  required,   and   an   opportunity   to   do   this   arose   when   the   manufacturing   company   Xylem   proposed  a  PSD  project  in  their  winding  shop.  

Xylem  is  a  world-­‐leading  provider  of  fluid  technology  and  equipment  solutions   for   water-­‐related   issues   (Xylem   Inc.,   2012).   Currently   the   company   is   in   the   planning   phase   of   developing   a   new   production   system,   and   as   a   response   to   cope  with  the  dynamic  competitive  environment,  the  company  at  the  same  time   wants  to  improve  the  productivity,  reduce  the  scrap  rate,  and  increase  the  ergo-­‐ nomics  in  this  new  production  system.  

1.2  Purpose  and  Research  Questions  

The  purpose  with  the  thesis  work  is  to  evaluate  the  usability  of  PSDFs  in  prac-­‐ tice.  In  order  to  achieve  this  purpose,  two  research  questions  have  been  estab-­‐ lished:  

RQ1.   How  can  usability  of  frameworks  be  evaluated?  

RQ2.   How  does  the  use  of  a  framework  contribute  to  the  development  of  a  new  

production  system?  

1.3  Delimitations  

Since   the   development   of   a   new   production   system   is   a   long   process   and   the   timeframe   for   this   thesis   work   is   limited   to   30   credits   (i.e.,   20   weeks   full-­‐time   study),  the  thesis  work  will  not  cover  the  actual  production  system  realization.   In  order  to  evaluate  the  usability  of  frameworks,  the  students  will  use  Bellgran   and  Säfsten’s  PSDF.  Moreover,  in  this  thesis  work  the  framework  will  only  been   used  and  tested  at  one  company.  

Finally,  the  thesis  work  is  limited  to  the  development  of  three  production  lines   and  to  the  requirements  set  by  the  company.  

1.4  Outline  

Chapter  2  –  Theoretical  Background  

This   chapter   mainly   presents   two   central   theoretical   aspects   connected   to   the   thesis  work.  The  first  aspect  is  production  system,  where  emphasis  is  put  on  the   development  through  the  use  of  frameworks.  The  second  aspect  is  usability  and   how  it  can  be  used  when  evaluating  frameworks.      

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Chapter  3  –  Method  

This  chapter  presents  the  methods  used  in  the  thesis  work.  A  thorough  explana-­‐ tion  of  all  used  data  collection  techniques  is  given  together  with  an  evaluation  of   data  quality.    

Chapter  4  –  Case  Description  

This  chapter  presents  the  results  from  the  PSD  process,  where  a  production  sys-­‐ tem  solution  was  developed  at  Xylem  by  the  use  of  Bellgran  and  Säfsten´s  PSDF.  

Chapter  5  –  Usability  Analysis  of  Production  System  Development  Framework  

This  chapter  presents  the  result  from  the  meta-­‐study  performed  on  the  PSD  pro-­‐ cess.  The  definition  of  usability,  together  with  the  estimation  levels  of  usability,  is   introduced.  Based  on  this,  the  actual  usability  analysis  is  presented  and  compiled   in  a  table  at  the  end  of  the  chapter.  

Chapter  6  –  Discussion  and  Conclusion  

In  this  chapter,  a  discussion  is  held  based  on  the  analysis.  Through  the  discus-­‐ sion,  conclusions  are  drawn,  which  answer  to  the  thesis  work’s  established  re-­‐ search   questions.   As   a   final   discussion,   critique   to   the   thesis   work’s   chosen   methods  is  given  and  suggestions  for  future  research  are  presented.  

Appendix  A-­‐C  

The   appendices   are   available   for   the   reader   who   wants   in-­‐depth   information   about  the  results  from  the  PSD  process.  The  appendices  are  documents  created   to  assist  the  PSD  process  and  are  the  result  of  following  Bellgran  and  Säfsten’s   PSDF.  The  attached  appendices  are  Plan  for  production  system  development  (A),  

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2.  Theoretical  Background  

This   chapter   mainly   presents   two   central   theoretical   aspects   connected   to   the  thesis  work.  The  first  aspect  is  production  system,  where  emphasis  is  put   on  the  development  through  the  use  of  frameworks.  The  second  aspect  is  us-­‐ ability  and  how  it  can  be  used  when  evaluating  frameworks.  

2.1  Production  System  

A  production  system  is  a  system  where  a  product  is  produced  physically  (Bell-­‐ gran  and  Säfsten,  2010),  and  the  function  of  a  production  system  can  generally   be  regarded  as  a  transformation  process  where  input  is  transformed  into  output   (Olhager,   2000).   Input   can   consist   of   material,   labor,   and   capital,   while   output   can  be  a  product  or  service.  It  is  during  the  transformation  process  that  value  is   created  for  the  customer.  Value  is  the  amount  a  customer  is  prepared  to  pay  for  a   product   or   service   (Porter,   1985,   see   Olhager,   2000,   p.   17).   In   order   to   get   the   most  value  of  a  resource  as  possible,  one  needs  to  design  production  processes   that   facilitate   efficient   and   effective   production   systems,   but   one   also   needs   to   manage  the  operations  so  they  produce  products  that  are  economically  advanta-­‐ geous  in  a  competitive  environment  (Arnold  et  al.,  2008).  

According   to   Bellgran   and   Säfsten   (2010),   a   holistic   perspective   is   important   when  considering  a  production  system,  and  this  is  since  a  production  system  is   an  open  system  and  constantly  affected  by  external  factors.  A  holistic  perspective   can  be  achieved  by  adapting  a  system  perspective,  which  is  a  way  of  focusing  on   all   factors   affecting   the   system   in   order   to   understand   the   system   as   a   whole   (Bellgran  and  Säfsten,  2010).  Chryssolouris  (1992)  has  a  similar  view  as  he  de-­‐ scribes  production  as  a  system  based  on  equipment  and  humans  bound  by  com-­‐ mon  material  and  information  flow.  

A   production   system   can   be   classified   in   several   different   ways   depending   on   perspective.   An   example   of   production   system   classification   is   the   hierarchical   perspective  (Seliger  et  al.,  1987,  see  Bellgran  and  Säfsten,  2010,  p.  41);  the  pro-­‐ duction   system   is   viewed   as   a   part   of   a   manufacturing   system,   and   consists   of   assembly  system  (or  line)  and  parts  production  system,  see  figure  2.1.  

  Figure  2.1   A  hierarchical  perspective  on  production  system  (Bellgran  and  Säfsten,  2010)  

A  production  system  is  thus  linked  to  other  systems,  and  can  be  affected  by  fac-­‐ tors  from  both  inside  and  outside  the  system.  Bellgran  and  Säfsten  (2010)  have   identified  three  general  factors  that  affect  a  production  system:  

1. External   influences:   history,   trends,   globalization,   and   company   struc-­‐ tures;  

2. Actual   options:   technology,   work   environment   and   organization,   and   planning  and  control;  and  

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3. Strategies  and  fundamental  attitudes:  management  strategies,  production   philosophies,  and  company  culture.  

2.1.1  Production  System  Development  

In  order  to  be  able  to  classify  reasons  for  changes  in  an  organization,  Porras  and   Robertson   (1992)   have   developed   a   model   where   various   degrees   of   organiza-­‐ tional   change   are   related   to   internal   and   external   reasons,   see   table   2.1.   If   a   change   is   triggered   by   reasons   from   inside   the   company,   it   is   most   likely   a   planned  change,  and  consequently,  if  a  change  is  triggered  by  reasons  from  out-­‐ side   the   company,   it   is   most   likely   an   unplanned   change.   To   which   degree   the   change   is   made   is   also   separated;   if   the   change   is   minor,   compared   to   current   conditions,  it  is  called  a  first-­‐order  change,  and  if  it  is  more  radical  it  is  called  a   second-­‐order  change  (Porras  and  Robertson,  1992).  

Table  2.1   Different  categories  of  change  (modified  from  Porras  and  Robertson,  1992)  

  Planned  change   Unplanned  change   First  order  change   Developmental   Evolutionary  

Second  order  change   Transformational   Revolutionary  

The  reasons  for  companies  to  develop  new  production  systems  can  emerge  from   different  perspectives:  

• Logistic  perspective:  companies  competing  worldwide,  transportation  and   movement  of  material  are  cheaper,  more  effective,  and  faster  (Arnold  et  

al.,  2008);  

• Product  perspective:  shortened  product  lifecycles  forces  companies  to  fo-­‐ cus  on  product  development  (Almgren  1999;  Surbier  et  al.,  2009);  and   • Work   environment   and   ergonomic   perspective:   stricter   legislations   force  

companies  to  think  about  their  employees’  health  and  wellbeing  (Christ-­‐ mansson  et  al.,  2000;  Jensen,  2002).  

All   of   these   reasons   for   developing   production   systems   are   based   on   the   same   basic   idea:   To   increase   the   profitability   for   the   company.   This   is,   however,   the   primary  objective  for  any  profit-­‐driven  company  (Olhager,  2000).  

According  to  Slack  and  Lewis  (2008),  a  company  requires  a  strategy  to  achieve   its  goals,  and  one  crucial  aspect  in  a  strategy  is  to  reconcile  the  market  require-­‐ ments  with  the  company’s  resources.  The  reconciliation  can  also  be  described,  as   how  well  the  company  manages  to  meet  its  customer  demands  (Slack  and  Lewis,   2008).  

How  well  a  company  is  performing  is  to  a  large  extent  depending  on  how  well  it   aligns  its  performance  objectives  with  its  customer  demands  (Slack  and  Lewis,   2008).   These   performance   objectives   can   to   some   degree   vary   from   different   authors.  Ferdows  and  De  Meyer  (1990)  illustrate  the  performance  objectives  in  a   sand  cone  model  including  quality,  dependability,  speed,  and  cost  efficiency,  see   figure  2.2.  The  basic  idea  behind  this  model  is  to  show  the  performance  objec-­‐ tives  to  be  cumulative.  Slack  and  Lewis  (2008),  on  the  other  hand,  view  perfor-­‐ mance   objectives   as   generic,   changeable   factors.   As   a   response   to   the   dynamic  

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market,  Slack  and  Lewis  have  also  added  flexibility  as  a  fifth  performance  objec-­‐ tive.  

 

Figure  2.2   Sand  cone  model  illustrating  the  cumulativeness  between  quality,  dependability,  speed,   and  cost  efficiency  (Ferdows  and  De  Meyer,  1990)  

Another  way  of  improving  a  company’s  performance  is  to  make  use  of  the  poten-­‐ tial  in  ergonomics  (Eklund,  2003)  since  a  lack  of  focus  on  ergonomics  can  affect  a   company’s  competitiveness  severely  (Neumann  et  al.,  2002).  

International   Ergonomics   Association   (2000)   defines   ergonomics,   or   “human   factors”,   as   “the   scientific   discipline   concerned   with   the   understanding   of   the   interactions  among  humans  and  other  elements  of  a  system,  and  the  profession   that  applies  theoretical  principles,  data  and  methods  to  design  in  order  to  opti-­‐ mize  human  wellbeing  and  overall  system”.  Although  the  definition  clearly  states   that   ergonomics   has   a   direct   impact   on   a   system’s   efficiency,   ergonomics   is   commonly  interpreted  in  a  more  narrow  sense  with  focus  on  only  human  factors   (Eklund,  2003).  

Helander   and   Burri   (1995)   argue   the   increased   need   for   ergonomic   design   in   today´s   manufacturing   environment   is   a   result   of   the   increased   technological   complexity.   For   instance,   an   operator   that   is   working   with   an   automated   ma-­‐ chine  must  both  take  a  supervising  role  and  repair  the  machine  in  case  of  mal-­‐ function,   as   well   as   a   be   a   back-­‐up   to   produce   manually   if   the   machine   breaks   down.    

2.1.2  Academic  versus  Industrial  Perspective  in  Production  System     Development  

The   view   of   PSD   tends   to   vary   between   theory   and   practice,   and   a   distinction   between   the   two   perspectives   can   be   made   (Bellgran   and   Säfsten,   2010).   Chryssolouris  (1992)  argues  the  most  common  industrial  approach  is  trial-­‐and-­‐ error.  However,  Bellgran  and  Säfsten  (2010)  mean  this  description  is  a  large  ex-­‐ aggeration,  although  they  agree  that  the  use  of  a  systematic  approach  in  industry   is  limited  due  to  several  reasons.  

Duda  (2000)  means  that  many  industrial  companies  follow  some  kind  of  “design   philosophy”,  which  guides  them  in  their  PSD  process.  Being  a  philosophy  is  nei-­‐ ther   defined   explicitly,   nor   includes   a   structured   methodology.   However,   a   de-­‐ sign  philosophy  can  have  profound  impact  on  an  organization  and  its  develop-­‐ ment  of  production  systems  (Duda,  2000).  The  most  known  example  of  a  design   philosophy  today  is  Toyota  Production  System  (e.g.,  Womack  et  al.,  1991;  Ohno,  

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1995;   Monden,   1998;   Liker,   2003);   despite   never   being   documented   into   any   formal   written   specification,   Toyota´s   huge   success   has   made   competitors   and   researchers   aware   of   their   approaches   towards   PSD,   they   have   analyzed   them,   and  they  have  also  imitated  them  (Duda,  2000).    

Christmansson   and   Rönnäng   (2003)   have   investigated   the   industrial   PSD   pro-­‐ cess   in   their   study   of   eleven   Swedish   companies.   There   they   identified   several   deficiencies  in  how  companies  developing  new  production  systems:  

• Lack  of  structured  methods;  

• No   evaluation   of   either   the   finished   production   system   or   the   PSD   pro-­‐ cess;  

• Lack  of  routines  for  knowledge  transfer;  and   • Used  methods  were  performing  unsatisfactory.  

However,  these  results  were  unexpected  for  the  above,  mentioned  authors  since   a  lot  of  resources  had  been  invested  in  the  investigated  companies’  PSD  projects.   A   conclusion   to   this   might   be   that   the   resources   were   not   spent   on   the   “right   things”.   More   resources   should   instead   have   been   devoted   to   project   time,   knowledge,  and  tools  (Christmansson  and  Rönnäng,  2003).  

2.1.3  Production  System  Development  Frameworks  

A  framework  can  be  defined  as  “a  real  or  conceptual  structure  intended  to  serve   as  a  support  or  guide  for  the  building  of  something  that  expands  the  structure   into  something  useful”  (Whatis,  2008).  Khademhosseinieh  and  Seigerroth  (2011)   describe  a  framework  as  a  structured  methodology  consisting  of  several  closely   linked  method  components.  Frameworks  are  generally  more  prescriptive  than  a   structure   and   thus   they   provide   directions   for   structures   to   follow   (Whatis,   2008).  

In  order  to  have  a  structured  work  method,  one  must  ensure  sufficient  time  is   spent   on   the   planning   stage   in   the   beginning   of   the   project   (Johansson,   2008).   According  to  Bellgran  and  Säfsten  (2010),  a  structured  work  method:  

• reduces  the  time  spent  on  structuring  work  procedures;  

• facilitates  the  coordination  and  management  of  the  project;  and     • provides  opportunities  for  well-­‐thought  out  system  solutions.  

A  thoroughly  planned  project  will  make  the  realization  phase  smoother,  faster,   cheaper,  and  less  troublesome.  However,  the  use  of  accurately  planned  projects   is  usually  lacking  in  industry,  where  it  instead  is  more  common  to  use  an  ad  hoc   approach  (Bellgran  and  Säfsten,  2010).    

According  to  Johansson  (2008),  the  area  of  industrial  PSD  is  both  large  and  com-­‐ plex,  and  this  has  made  many  researchers  reluctant  to  develop  their  own  frame-­‐ works   covering   the   whole   PSD   process.   According   to   Bellgran   and   Säfsten   (2010),  frameworks  are  lacking  when  it  comes  to  present  concrete  methods  for   optimal  solutions,  and  they  are  not  leading  to  a  detailed  PSD.  The  lack  of  frame-­‐ works,   containing   the   whole   PSD   process,   has   inspired   many   companies   to   de-­‐ velop  their  own  methods  for  how  their  concepts  and  ideas  about  how  production   systems   should   be   designed   (Duda,   2000).   Bellgran   and   Säfsten   (2010)   mean   that  there  are  four  integrated  theories  that  handle  the  production  system  design:  

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• Design   frameworks   and   strategies:   involve   manufacturing   strategy,   but   lacks  a  methodology  for  choosing  between  design  alternatives  and  thus  it   does  not  lead  to  detailed  designs;  

• Philosophies   with   sets   of   techniques   and   methods:   certain   techniques   and   methods  supporting  different  philosophies  (e.g.,  JIT,  TPM,  and  Kaizen);   • Design   by   philosophy:   integrated   approach   to   production   system   design  

and   is   based   on   what   constitutes   a   good   production   system   (e.g.,   TPS);   and  

• System   engineering:   top-­‐down   design   approach   aimed   at   creating   prod-­‐ ucts,  systems,  and  structures  that  are  competitive.  

Even   if   the   focus   on   the   interrelationship   between   products   and   production   is   important,  focus  within  the  industry  is  mostly  directed  to  the  product  develop-­‐ ment  area  (Bellgran  and  Säfsten,  2010).  Bellgran  and  Säfsten  (2010)  summarize   the  distinctions  between  the  development  processes  within  the  production  and   product  development  areas:  

The  process  of  developing  production  systems  has  not  been,  and   is   not,   focused   in   the   same   way   as   the   process   of   developing   products,  neither  in  academia  nor  in  industry.  (p.  5)  

This  gives  a  notion  that  the  product  development  area  focuses  more  on  the  pro-­‐ cess   than   the   production   development   area   does.   There   are   a   lot   of   different   frameworks  that  focus  on  the  product  development  process:  

• A  framework  for  the  product  development  process  (Ulrich  and  Eppinger,   2008);  

• An  empirically-­‐based  framework  for  analyzing  product  development  time   (Adler  et  al.,  1995);  

• A   model-­‐based   framework   to   overlap   product   development   activities   (Krishnan  et  al.,  1997);  and  

• A  framework  to  increase  innovation  and  flexibility  within  the  product  de-­‐ velopment  process  (Malhotra  et  al.,  1996).  

Within  the  product  and  production  development  areas,  there  are  parts  that  are   similar  and  thus  some  theoretical  aspects  are  applicable  in  both  fields.  However,   when   regarding   the   PSD   process   as   a   whole,   there   are   some   differences,   and   therefore  some  developed  frameworks  might  not  be  applicable  for  the  other  re-­‐ spectively  field  (Bellgran  and  Säfsten,  2010).  

Bellgran  and  Säfsten´s  Production  System  Development  Framework  

Bellgran   and   Säfsten´s   PSDF   is   built   upon   both   theoretical   and   empirical   data.   The  framework  puts  a  lot  of  focus  on  the  double  task,  which  means  the  planning   phase  is  separated  from  the  actual  accomplishment  phase  (Bellgran  and  Säfsten,   2010).  

Johansson   (2008)   describes   Bellgran   and   Säfsten’s   framework   as   “almost   com-­‐ pletely   comprehensive”   and   “very   ambitious”   compared   to   what   is   used   in   the   industry.   The   framework   also   includes   several   practical   aspects,   rarely   men-­‐ tioned  in  the  literature.  One  example  is  how  the  investment  request  needs  to  be   considered  in  the  early  stages  of  the  development  process.  Bellgran  and  Säfsten  

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also  emphasize  the  necessity  of  the  framework  to  adapt  to  each  separate  compa-­‐ ny  requirement  in  order  to  be  as  beneficial  as  possible.  

The  framework  consists  of  three  main  blocks,  each  containing  two  elements,  see   figure  2.3.  

 

Figure  2.3   Bellgran  and  Säfsten’s  production  system  development  framework  (Bellgran  and  Säfsten,   2010)  

To   assist   the   PSDF,   Bellgran   and   Säfsten   have   developed   a   Structured   way   of  

working,  which  provides  a  detailed  map  for  the  PSD  process,  see  figure  2.4.  The  

structure  ensures  that  all  aspects  within  a  phase  are  being  considered  and  doc-­‐ umented  at  the  end  of  every  element.  

Plan  

The  Plan  block  consists  of  the  elements  Structured  way  of  working  and  Manage-­‐

ment  and  control.  The  first  two  phases  result  in  a  document  called  Plan  for  pro-­‐ duction  system  development,   which   provides   the   input   data   for   the   next   phase,  

the  Preparatory  design  phase.  It  is  important  to  remember  that  data  in  this  doc-­‐ ument  are  not  static  but  may  change  as  the  project  proceeds.  However,  Bellgran   and  Säfsten  stress  the  importance  of  having  some  kind  of  control  and  quality  as-­‐ surance  document  as  a  starting  point.    

Design  and  Evaluate  

The  empirical  studies  made  by  Bellgran  and  Säfsten  showed  the  importance  of   separating  the  Preparatory  design  from  the  Design  specification.  In  the  Preparato-­‐

ry  design  one  evaluates  the  conditions  for  developing  a  new  or  existing  produc-­‐

tion   system.   This   is   done   by   first   reviewing   current   production   systems,   both   internally   and   externally,   in   a   Background   study.   After   this,   a   Pre-­‐study   is   per-­‐ formed   where   focus   is   on   the   future   state   of   the   production   system.   It   can   for   example   be   about   the   company   strategies   and   which   demands   the   production   system  might  face  in  the  future.  The  results  from  the  Background  study  and  Pre-­‐

study  are  finally  summarized  in  a  Requirement  specification.  

The   next   element,   the   Design   specification,   consists   of   three   phases.   Design   of  

conceptual  production  systems  is  the  process  of  generating  different  system  solu-­‐

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tion  systems.  The  solution  deemed  most  appropriate  according  to  the  previously  

established   requirements   is   then   developed   and   designed   in   detail   in   the   De-­‐

tailed  design  of  chosen  production  system.   Implement  

Input  to  the  next  phase  Build  production  system  is  the  System  solution.  It  is  in  this   phase  the  realization  of  the  production  system  begins.  Plan  start-­‐up  is  carried  out   in   parallel   to   the   when   the   System   solution   is   being   established.   The   success   of   the  Start-­‐up  is  a  direct  result  of  how  well  the  PSD  project  has  managed  to  meet   the  requirements  set  on  the  production  system,  as  well  as  the  quality  of  the  Plan  

start-­‐up  phase.   The   final   phase   of   this   structured   work   method   is   the   Evaluate   the  result  and  the  way  of  working  phase.  

Context  and  Performance  

The  part  Context  and  performance  is  of  a  different  nature  than  the  other  blocks   since   it   affects   all   the   other   three   blocks   throughout   the   whole   PSD   process.   Empirical  studies  show  the  contextual  aspects  to  be  of  such  dignity,  as  they  affect   both  the  planning  process  as  well  as  the  actual  development  process,  and  this  is   why  the  part  is  placed  separately  in  Bellgran  and  Säfsten’s  PSDF.  

 

Figure  2.4   Bellgran   and   Säfsten’s   Structured  way  of  working   with   production   system   development   (Bellgran  and  Säfsten,  2010)  

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2.2  Usability  

“Usability  refers  to  the  measure  of  success  of  the  product  –  whether  it  be  soft-­‐ ware,  computer  systems  or  a  product.”  (Faulkner,  2000,  p.  12)  Usability  is  mainly   mentioned  within  the  human-­‐computer  interaction  (HCI)  area,  which  is  a  part  of   the   product   development   area   (Zimmerman   et   al.,   2007).   Usability   consists   of   two  usability  dimensions  (Han  et  al.,  2000;  Hornbæk,  2006):  

1. Subjective  usability  measures:  measures  based  on  users’  perception  of  or   attitudes  towards  the  system,  interaction  or  outcome;  and  

2. Objective   usability   measures:   measures   that   can   be   obtained,   discussed,   and  validated  in  ways  not  possible  with  subjective  measures.  

When  designing  and  evaluating  systems,  these  two  usability  dimensions  are  con-­‐ sidered  equally  important  (Han  et  al.,  2000)  since  the  overall  acceptability  of  a   system  is  the  combination  of  both  its  social  and  practical  acceptability  (Nielsen,   1993).  Furthermore,  Hornbæk  (2006)  states  that  objective  and  subjective  usabil-­‐ ity   measures   can   lead   to   different   conclusions   regarding   system   usability,   and   using  both  usability  measures  gives  a  more  “complete  picture”  of  the  term  usa-­‐ bility.  

Shackel  (1991)  means  that  usability  is  mainly  mentioned  as  one  attribute  when   talking  about  acceptable  systems,  as  he  means  an  acceptable  system  also  has  to   be:  

• functional;  

• suitable  for  the  user;  and  

• balanced  in  a  trade-­‐off  against  cost.  

According  to  Shackel  (1991),  the  degree  of  usability  is  directly  linked  to  the  level   of  system  understandability.  Hence,  the  term  usability  has  big  impact  on  whether   a  system  is  acceptable  or  not,  and  therefore  it  is  essential  to  focus  on  it  as  a  cor-­‐ nerstone  to  system  success.  However,  a  big  problem  arises  when  trying  to  design   for  usability  as  usability  requires  skills  in  human  factors,  and  it  is  difficult  to  in-­‐ tegrate   usability   with   other   existing   design   processes   (Bevan   and   Macleod,   1994).    

Usability   is   context   dependent   (Newman   and   Taylor,   1999)   and   shaped   by   the   interaction   between   tools,   problems,   and   people   (Shackel,   1991;   Naur,   1992).   But   it   is   difficult   to   explicitly   describe   what   features   and   attributes   that   shape   usability,   since   features   and   attributes   depend   on   the   context   of   the   system   in   use  (Bevan  and  Macleod,  1994).  

Users  want  user-­‐friendly  systems  and  it  is  up  to  the  developers  to  produce  them;   if  a  system  is  difficult  to  use,  it  wastes  the  user’s  time,  causes  frustration  and  dis-­‐ comfort,  and  discourages  further  use  of  the  system  (Bevan  and  Macleod,  1994).   However,   usability   is   neither   one-­‐dimensional   nor   user   characteristic,   and   that   are  factors  that  make  usability  particularly  difficult  to  measure  and  even  harder   to   truthfully   evaluate   (Bevan   et   al.,   1991;   Shackel,   1991,   Nielsen,   1993;   Bevan   and  Macleod,  1994).  

According   to   Bevan   and   Macleod   (1994),   usability   can   be   viewed   in   different   ways,   for   different   purposes,   and   focus   on   one   or   more   of   the   three   following   corresponding  views:  

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1. The  product-­‐centered  view:   the   usability   of   a   product   is   the   attributes   of   the  product,  which  contribute  towards  the  quality  of  use;  

2. The  context  of  use  view:  usability  depends  on  the  nature  of  the  user,  prod-­‐ uct,  task,  and  environment;  and  

3. The  quality  of  use  view:  usability  is  the  outcome  of  interaction  and  can  be   measured   by   the   effectiveness,   efficiency,   and   satisfaction   with   which   specified  users  achieve  specified  goals  in  particular  environments.  

2.2.1  Definition  and  Description  of  Usability  

According   to   Jokela   et   al.     (2003),   the   “main   reference”   of   usability   is   the   ISO   9241-­‐11,   while   the   best-­‐known   definition   is   the   one   defined   by   Jakob   Nielsen.   The  ISO  9241-­‐11’s  definition  is  one  part  of  the  ISO  9241  standard  that  is  about   ergonomic  requirements  for  office  work  with  visual  display  terminals,  whereas   Nielsen’s  definition  is  developed  as  a  means  within  the  HCI  area.  Thus,  both  the   definitions  are  based  on  the  development  of  HCI  systems.  

The   ISO   9241-­‐11   (1998)   standard   defines   usability   as:   “The   extent   to   which   a   product  can  be  used  by  specified  users  to  achieve  specified  goals  with  effective-­‐ ness,  efficiency  and  satisfaction  in  a  specified  context  of  use”  (p.  2).  The  terms  in   the  definition  are  further  defined  as  (ISO  9241-­‐11,  1998):  

• Effectiveness:  accuracy  and  completeness  with  which  users  achieve  speci-­‐ fied  goals;  

• Efficiency:  resources  expended  in  relation  to  the  accuracy  and  complete-­‐ ness  with  which  users  achieve  goals;  

• Satisfaction:  freedom  from  discomfort,  and  positive  attitude  to  the  use  of   the  product;  and  

• Context   of   use:   characteristics   of   the   users,   tasks   and   the   organizational   and  physical  environments.  

Nielsen  (1993)  defines  usability  in  a  more  “ambiguous”  way  (Jokela  et  al.,  2003)   when  he  defines  the  term  with  five  different  usability  attributes:  

1. Learnability:  the  system  should  be  easy  to  learn  so  that  the  user  can  rap-­‐ idly  start  getting  some  work  done  with  the  system;  

2. Efficiency:  the  system  should  be  efficient  to  use,  so  that  once  the  user  has   learned  the  system,  a  high  level  of  productivity  is  possible;  

3. Memorability:  the  system  should  be  easy  to  remember,  so  that  the  casual   user  is  able  to  return  to  the  system  after  some  period  of  not  having  used   it,  without  having  to  learn  everything  all  over  again;  

4. Errors:  the  system  should  have  a  low  error  rate,  so  that  users  make  few   errors   during   the   use   of   the   system,   and   so   that   if   they   do   make   errors   they  can  easily  recover  from  them.  Further,  catastrophic  errors  must  not   occur;  and  

5. Satisfaction:  the  system  should  be  pleasant  to  use,  so  that  users  are  sub-­‐ jectively  satisfied  when  using  it;  they  like  it.  

Together  with  the  ISO  9241-­‐11  and  Nielsen’s  definitions  and  descriptions  of  usa-­‐ bility,  there  are  also  other  explanations  (also  based  on  the  development  of  HCI   systems)  of  what  attributes  usability  consists  of,  see  table  2.2.  

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Table  2.2   Usability  attributes  of  various  standards  or  models  (modified  from  Seffah  et  al.,  2006)  

Shackel  

(1991)   Schneiderman  (1992)   Nielsen  (1993)   Preece  et  al.  (1994)   ISO  9241-­‐11  (1998)   Constantine  and  Lockwood   (1999)  

Effectiveness  

(speed)   Speed  of  per-­‐formance   Efficiency  of  use   Throughput   Efficiency   Efficiency  in  use   Learnability  

(time  to  learn)   Time  to  learn   Learnability  (ease  of  learn-­‐ ing)  

Learnability   (ease  of  learn-­‐ ing)  

  Learnability  

Learnability  

(retention)   Retention  over  time   Memorability       Rememberability   Effectiveness  

(errors)   Rate  of  errors  by  users   Errors/safety     Effectiveness   Reliability  in  use   Attitude   Subjective  

satisfaction   Satisfaction   Attitude   Satisfaction  (comfort  and   acceptability  of   use  

User  satisfaction  

Jokela  et  al.  (2003)  state  that  a  lot  of  usability  efforts  and  challenges  are  directed   to   how   to   define   and   determinate   usability   requirements,   rather   than   how   to   measure,  evaluate,  and  test  usability.  However,  they  mean  this  to  be  a  good  de-­‐ velopment   since   it   is   “through   measurable   usability   requirements   the   usability   work   of   the   projects   becomes   more   recognized   and   goal-­‐driven”   (Jokela   et   al.,   2003,  p.  59).  

2.2.2  Measurement  of  Usability  

Measurement  of  usability  attends  to  make  the  term  usability  more  concrete  and   easier  to  evaluate  (Hornbæk,  2006).  When  one  wants  to  measure  usability,  it  is   important  to  measure  aspects  that  are  relevant  for  the  use  of  the  system.  Bevan   and  Macleod  (1994)  describe  this  as:  “context  of  measurement  must  match  con-­‐ text  of  use”  (p.  7).  The  challenge  here  is  to  “develop  subjective  measures  for  as-­‐ pects   of   quality-­‐in-­‐use   that   are   currently   mainly   measured   by   objective   measures,  and  vice  versa,  and  evaluate  their  relation”  (Hornbæk,  2006,  p.  92).     According  to  Hornbæk  (2006),  measurement  of  usability  has  three  motivations:  

1. The  meaning  of  the  term  usability  is  to  a  large  extent  determined  by  how   one  measure  it;  

2. Usability   cannot   be   directly   measured   and   uncover   validity   problems   in   how  usability  is  operationalized  and  reasoned  about;  and  

3. The  majority  of  approaches  to  user-­‐centered  design  depend  critically  on   measures  of  the  quality  of  interactive  systems.  

Nielsen  (1993)  argues  the  most  traditional  way  to  measure  usability  is  to  use  a   number  of  test  users  that  fill  in  their  answers  with  help  of  various  grading  scales   (e.g.,  Likert  scale).  Thus,  the  grading  scales  make  the  answers  quantifiable.  Based   on   the   result   one   normally   takes   the   mean   value   of   each   of   the   attributes   and   combine  these  into  a  single  usability  factor  (Nielsen,  1993).  

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The  most  common  measures  of  usability  are  effectiveness,  efficiency,  and  satis-­‐ faction   (Bevan   and   Macleod,   1994;   Hornbæk,   2006),   but   there   also   exist   other,   broader  measures,  for  example,  flexibility  and  low  rate  of  errors.  However,  Bev-­‐ an   and   Macleod   (1994)   mean   measuring   effectiveness,   efficiency,   and   satisfac-­‐ tion   across   a   range   of   contexts   makes   it   possible   to   assess   these   broader   measures,  which  flexibility,  low  rate  of  errors  etc.  are.  

2.2.3  Evaluation  of  Usability  

According  to  Rosson  and  Carroll  (2002),  “usability  evaluation  is  any  analysis  or   empirical  study  of  the  usability  of  a  prototype  or  system”  (p.  227).  Evaluation  of   usability   is   an   essential   procedure   in   system   development   (Kwahk   and   Han,   2002),  and  consists  of  iterative  cycles  of  designing,  prototyping,  and  evaluating   (Nielsen,  1993).  Most  usability  evaluation  methods  tend  to  be  quantitative,  but  in   order  to  evaluate  a  system  thoroughly,  it  is  necessary  to  gain  and  evaluate  quali-­‐ tative  measures  as  well  (Faulkner,  2000).  

There  are  three  common  activities  when  evaluating  usability  (Ivory  and  Hearst,   2001):  

1. Capture:  measuring  and  collecting  usability  data;  

2. Analysis:  interpreting  usability  data  to  identify  usability  problems  in  the   interface;  and  

3. Critique:  suggesting  solutions  or  improvements  to  mitigate  problems.     Since  evaluation  is  based  on  measures,  usability  evaluation  also  has  to  take  place   in  an  appropriate  context  of  use  (Shackel,  1991;  Nielsen,  1993).  In  order  to  have   a  good  alignment  between  measures  and  evaluation  of  usability,  Bevan  and  Mac-­‐ leod  (1994)  argue  a  description  of  the  context  of  measurement  is  crucial  for  an   evaluation  report.  

Wixon  (2003)  propose  three  important  aspects  to  focus  on  when  trying  to  evalu-­‐ ate  usability  as  accurately  as  possible:  

1. Learn  all  from  own  practice;  

2. Evaluate   methods   by   applying   them   to   real   products   embedded   in   real   engineering,  corporate,  and  political  environments  and  not  on  simulated   systems  or  hypothetical  models;  and  

3. Adopt  a  case  study  rather  than  an  experimental  approach.  

Findings   from   usability   evaluation   tend   to   be   unsystematic   and   unpredictable   (Ivory  and  Hearst,  2001).  For  instance,  different  usability  evaluators  studying  the   same  user  interface  can  come  up  with  widely  spread  usability  findings  (Nielsen,   1993).   To   uncover   unsystematic   and   unpredictable   usability   evaluations,   one   solution   is   to   increase   the   number   of   evaluators   and   study   participants   (Ivory   and  Hearst,  2001).  

2.2.4  Usability  of  Frameworks  

As  stated  earlier,  the  theory  of  usability  is  mainly  covered  within  the  HCI  area.   However,  there  is  nothing  that  says  usability  is  important  only  for  HCI  systems.   In   fact,   usability   is   important   to   consider   for   any   product,   system,   or   service   (Chincholle  et  al.,  2002).  

In  a  way,  frameworks  and  HCI  systems  are  similar  as  they  both  aim  to  guide  a   user  to  accomplish  a  task.  However,  a  HCI  system  is  a  coherent  collection  of  ob-­‐

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jects  (Carzaniga  et  al.,  1998),  while  a  framework  is  a  prescriptive  structure  that   guides   objects   in   a   system   to   perform   something   useful   for   the   user   (Whatis,   2008).  Therefore,  it  is  believed  the  use  of  HCI  systems  is  more  straightforward   and  clear  compared  to  the  use  of  frameworks.  

Due  to  the  strong  alignment  between  definition,  measurement,  and  evaluation  of   usability  (i.e.,  they  are  all  context  dependent),  combined  with  the  similar  charac-­‐ teristic  between  frameworks  and  HCI  systems,  the  evaluation  methods  used  for   evaluating   usability   in   systems   within   the   HCI   area   (see   section   2.2.3)   are   be-­‐ lieved   to   be   applicable   also   for   the   evaluation   of   frameworks.   However,   to   be   able  to  evaluate  usability  of  a  framework,  one  needs  to  define  what  usability  of   frameworks  means.  

Within  the  HCI  area,  researchers  (e.g.,  Shackel,  1991;  Schneiderman,  1992;  Niel-­‐ sen,   1993;   Bevan   and   Macleod,   1994;   Preece   et   al.,   1994;   ISO   9241-­‐11,   1998;   Constantine  and  Lockwood,  1999)  have  comprised  the  term  usability  with  words   like   effectiveness,   efficiency,   learnability,   memorability,   flexibility,   low   rate   of   errors,  and  satisfaction.  Summarizing  these  usability  terms,  using  a  framework,  it   gives  that  a  framework  should:  

• fulfill  its  objectives  (effective);   • be  easy  to  learn  (learnable);   • be  easy  to  use  (efficient);  

• be  easy  to  memorize  (memorable);  

• be  designed  so  the  user  cannot  operate  it  wrong  (low  rate  of  errors);   • be   able   to   be   used   with   other   methods,   tools,   and   systems   (adaptable);  

and  

• be  convenient  to  use  (satisfactory).  

However,   low   rate   of   errors   and   adaptability   are   something   that   is   measured   implicitly  when  measuring  satisfaction,  efficiency,  and  effectiveness  (Bevan  and   Macleod,  1994).  In  order  to  evaluate  usability  of  frameworks,  it  is  thus  believed   that  one  can  use  learnability,  memorability,  efficiency,  effectiveness,  and  satisfac-­‐ tion,  and  doing  this  based  on  the  following  definitions:  

Learnability:  capability  of  a  framework  to  enable  a  user  to  learn  it   Memorability:  capability  of  a  framework  to  enable  a  user  to  mem-­‐

orize  it  

Efficiency:  resources  expended  in  relation  to  achieved  results   Effectiveness:   accuracy   and   completeness   with   which   users  

achieve  specified  goals  

Satisfaction:   freedom   from   discomfort,   and   positive   attitudes   to-­‐

wards  the  use  of  a  framework  

Figure

Figure	
  2.1	
   A	
  hierarchical	
  perspective	
  on	
  production	
  system	
  (Bellgran	
  and	
  Säfsten,	
  2010)	
  
Table	
  2.1	
   Different	
  categories	
  of	
  change	
  (modified	
  from	
  Porras	
  and	
  Robertson,	
  1992)	
  
Figure	
  2.2	
   Sand	
  cone	
  model	
  illustrating	
  the	
  cumulativeness	
  between	
  quality,	
  dependability,	
  speed,	
   and	
  cost	
  efficiency	
  (Ferdows	
  and	
  De	
  Meyer,	
  1990)	
  
Figure	
  2.3	
   Bellgran	
  and	
  Säfsten’s	
  production	
  system	
  development	
  framework	
  (Bellgran	
  and	
  Säfsten,	
   2010)	
  
+7

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