1. 1 Vrije Universiteit Faculty of Sciences Department of Computer Science Section Information Management & Software Engineering Sub section Human Computer Interaction, Multimedia & Culture Johan F. Hoorn Sources of Requirements Change. A Goal and Viewpoints-driven Explanation

2. 2 Contents  Status  Problem: Requirements change  The requirements-analysis rift  The goals-to-requirements chiasm  Stakeholder logistics  Conclusions/Discussion  Questions Johan F. Hoorn, 2005 M M I 9 9 0 0 9

3. 3 Status  Postdoc project: 2001-Aug 2005  Supervisors: Gerrit van der Veer and Hans van Vliet  Six international publications, three pending  Mens-Machine Interactie  Supervising committee Johan F. Hoorn, 2005

4. 4 Status (2)  Industries involved Johan F. Hoorn, 2005

5. 5 Problem  Requirements change Johan F. Hoorn, 2005 Software development-track Requirements elicitation Requirements negotiation System specification Software implementation System design Change requirements The later a change occurs, the more costs are involved in redesign $$$$$$ $$$$$$$$$$$$$$$

6. 6 Johan F. Hoorn, 2005 The requirements-analysis rift  Stakeholders regard requirements as something of the business  Stakeholders regard goals to achieve with the system as something personal  They fail to see the connection - it’s a viewpoints problem Requirements: Business viewGoals: Personal view Focus switch

7. 7 Johan F. Hoorn, 2005  Capacity Management System  Police Academy students (novice users)  Scored agreement to requirements and goals from business or personal viewpoint How do we know?

8. 8 F (1,30) = 10.19, p=.003, η p 2 =.25. Parameter coefficient=.91, t= 3.19, p<.004

9. 9 Johan F. Hoorn, 2005 The goals-to-requirements chiasm  Requirements that the system MUST have change due to situations stake- holders want to AVOID  Requirements that the system WON’T have change due to situations stake- holders want to ACHIEVE

10. 10  Capacity Management System (police officers)  Logistic Warehouse Management System (managers)  Commercial Off-the-Shelf Computers (interaction designers)  Braille Mouse (blind pupils) How do we know? Johan F. Hoorn, 2005

11. 11 Type of questions must/won’tsupport/obstructgoal approach/avoid E-mail orderingincreasesefficiency E-mail orderingdecreasesefficiency E-mail orderingincreasesinefficiency E-mail orderingdecreasesinefficiency Paper ordering formsincreaseefficiency Paper ordering forms decreaseefficiency Paper ordering forms increaseinefficiency Paper ordering forms decreaseinefficiency Example items Johan F. Hoorn, 2005

12. 12 Four replications R 2 adj =.90, F (5,12) = 30.30, p=.000 R 2 adj =.70, F (5,12) = 9.01, p=.001 R 2 change =.16, F (2,11) = 11.88, p=.002 COTS R 2 adj =.65, F (5,8) = 5.84, p=.015 R 2 adj =.73, F (2,11) = 18.28, p=.000 R 2 adj =.31, F (1,13) = 7.30, p=.018 R 2 adj =.23, F (1,13) = 5.18, p=.040 Johan F. Hoorn, 2005

13. 13 What if the rift co-occurs with the chiasm? Johan F. Hoorn, 2005

14. 14 Problem revisited  Requirements change Johan F. Hoorn, 2005 Software development-track System design Software implementation System use Change requests The later a change occurs, the more costs are involved in redesign $$$$ $$$$$$$$$$$ $$$$$$$$$$$$$$$$$$$$$

15. 15 Stakeholder logistics Johan F. Hoorn, 2005 SatisfactionUsabilityEfficiency Effort Effectiveness Performance R 2 =.16, F (1,926) = 181.85, p=.000 16% R 2 =.34, F (1,925) = 236.58, p=.000  =.25  =.35 - Survey among 1943 employees - 25 different banking systems

16. 16 - You ask for their goals - You specify requirements to serve these goals - You go back to the work floor - They agree more or less to what you propose - And then while using the system they start complaining that it does not serve them well Johan F. Hoorn, 2005 Conclusions/Discussion (1)  Beware of the requirements-analysis rift (changes in viewpoints)

17. 17 Ask them:  What are the things you want to achieve with the system?  What should the system NOT have to support that?  What are the things you want to avoid with the system?  What should be ON the system to support that? Johan F. Hoorn, 2005 Conclusions/Discussion (2)  Beware of the goals-to-requirements chiasm (changes come from crossed relations)

18. 18 In most of our studies, personal goals at work were related to  Effectiveness (e.g., getting targets, less costs, help colleagues)  Efficiency (e.g., being fast and accurate, better planning)  Effort (e.g., less work load, comprehensibility) Johan F. Hoorn, 2005 Conclusions/Discussion (3)  Look at lower-level personal goals (changes do not come from source concerns)

19. 19 Questions? Johan F. Hoorn, 2005 Requirements change M M I 9 9 0 0 9