1. Normative & Descriptive Approaches to Work Analysis Psych 562 Week 3 Discussion Shane Davis

2. Work Analysis Systematic investigation of work, jobs, and the relationships among jobs Three categories – Normative “What should be” – Descriptive “What is” – Formative “What could be”

3. Normative Approach How the system “should” behave Example: Task analysis – Input/Output “Black box” – Sequential Flow Step-by-step – Timeline Remember GOMS?

4. A Real-World Analogy Input/OutputSequential Flow / Timeline “What should be done”“What shouldn’t be done” Inputs: Miles traveled since last fill-up Gallons at this fill-up Output: Gas consumption rate (Km/L) Constraints: 1 mile = 1.609 Km 1 gallon = 3.785 Liters 1.Read current odometer value (2 sec) 2.Read odometer value at last fill-up (2 sec) 3.Calculate difference (5 sec) 4.Multiply by 1.609 (5 sec) 5.Let this value equal X 6.Read gallons at this fill-up (2 sec) 7.Multiply by 3.785 (5 sec) 8.Let this value equal Y 9.Divide X by Y (5 sec)

5. Task Analysis: Constraints Vs. Instructions Constraints Less detailed – More worker discretion Health benefits Less guidance – Greater risk of error Accommodates variability – More learning opportunities More device-independent – Fewer assumptions Instructions More detailed – Less worker discretion Health risks More guidance – Lesser risk of error Little room for variability – Fewer learning opportunities More device-dependent – More assumptions

6. The Problem With Instruction: The Task-Artifact Cycle Because instruction-based analyses are relatively device- dependent, any change to the device designs affects workers’ tasks, subsequently necessitating new device designs, etc.

7. Closed and Open Systems Closed system = predictable; isolated from environment – Does a truly closed system actually exist? Open system = dynamic; susceptible to environmental disturbances – Context-conditioned variability – Examples? Continuum, not a dichotomy – The more open a system is, the less appropriate instruction-based analyses are

8. Work Domain Analysis: Shifting Focus from Task to Structure Task Analysis (Event Dependent) Work Domain Analysis (Event Independent)

9. What to Take from Normative Analyses Instruction-based analyses, while common, aren’t well-suited for complex open systems Constraint-based analyses allow for worker discretion and device independence – Cannot account for novel situations and events But work domain analysis can

10. Descriptive Approach Normative = “ideal” Descriptive = “real” – What do workers actually do in practice? Task vs. activity – Field studies Is one of these approaches better?

12. Why Descriptive? Can lead to unique insights Examine how theory matches up with reality – Context-conditioned variability – Communication and teamwork – Tools and artifacts – History and culture – Expertise Normative is not enough

13. Descriptive is Not Enough Our observations of real-world practices are device dependent and can lead us to conflate “workaround” and “functional” actions while overlooking novel possibilities that may address intrinsic constraints.

14. Descriptive is Not Enough Techniques such as rapid prototyping can help overcome the limitations of a descriptive approach, but they are still subject to the task-artifact cycle, are bound by creativity, and cannot predict unique events.

15. Possible Solution: Modeling Model intrinsic work constraints – E.g. Traffic regulations; laws of physics – NOT issues with current design(s) Why model? – Synthesize data – Make predictions Of course, not always feasible

16. Summary Normative and descriptive approaches are both useful but not independently sufficient Work analysis should include: – Constraint-based analyses – Work domain analyses – Expertise, historical/cultural factors, etc. By integrating idealistic goals with current practices we can develop formative approaches – Design as an output, not an input

17. Thank you! Questions, comments, etc.