1. 1 As Class Convenes u Find your team u Sign attendance form u Insert any work due today and u Return folder to the front desk

2. 2 Session Agenda u Evaluating Alternatives40 min u Working on Project (review of some notebook work)35 min

3. 3 Learning Objective Achieve awareness of the differences between Relative Ratings and Absolute Ratings in completing Scoring Tables (Matrices)

4. 4 Sample Scoring Table

5. 5 Determining Ratings: The Text Book Says u Use relative comparisons u Use a simple rating scale 1 = much worse than reference to 5 = much better than reference

6. 6 Problems With Relative Rating u Scale Compression –if reference concept is the best relative to criterion 1, what rating values are available for criterion 1? –only 1 (much worse), 2 (worse) & maybe 3 (same) u Not rigorous for non experts

7. 7 In Some Cases We Can Do Better u Use absolute instead of relative rating of concepts u Use engineering science to predict the values of the criteria for the concepts

8. 8 The Weighted Objectives Method [1]  List Design Objectives  Rank-order the list  Assign Relative weights to objectives  Establish performance parameters or utility scores for each objective  Calculate relative utility values for alternatives

9. 9 Reference for Today’s Material [1] N. Cross, “Evaluating Alternatives,” in Engineering Design Methods, Chichester, John Wiley and Sons, 1989, pp. 101-121.

10. 10 1. List Design Objectives u Decision requires criteria (objectives) u Includes: –Technical factors –Economic factors –User requirements –Safety requirements –Etc.

11. 11 2. Rank-order Objectives u Individual: Ordered set of note cards to indicate relative importance u Team: pair wise comparison matrix or table

12. 12 Pairwise Comparison ABC A B C

13. 13 Pairwise Comparison ABC A1 B0 C

14. 14 Pairwise Comparison ABC A11 B0 C0

15. 15 Pairwise Comparison ABC A11 B01 C00

16. 16 2. Rank-ordering continued u Order established u The ordering is an ordinal scale u Ordinal scales should not be used in arithmetical operations

17. 17 3. Assign Relative Weightings to Objectives u Use rank ordering to spread out along a 1 to 10 scale u Assign a fixed number of points, say 100) among the objectives u Utilize an Objectives Tree

18. 18 Example Objectives Tree G1 1.0 G11 0.5 G12.25 G13.25 Manufacturing Cost Aesthetically Pleasing Long Lasting G111 0.60.3 G112 0.40.2 Cost of Materials Cost of Assembly

19. 19 3. Assign Relative Weightings Continued u The relative weightings are an interval value scale u Interval value scales can be used in arithmetic operations

20. 20 4. Establish Utility Scores for Objectives u Need to convert objectives into things measured (metrics) u Establish a scale to define what is good; what is bad

21. 21 Two Sample Scales 11 Pt Scale Meaning5 Pt ScaleMeaning 0Total useless0Inadequate 1 2Very poor1Weak 3Poor 4Tolerable 5Adequate2Satisfactory 6 7Good3 8Very good 9Excellent4 10Perfect

22. 22 Scale for Car Objectives ScaleFuel Consumption (miles/gal) Comfort 0<27Very uncomfortable 129Poor Comfort 232Below Average Comfort 335Average Comfort 438Above Average Comfort 541Good Comfort 6>43Extremely Comfortable

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26. 26 Calculate Relative Utility Values for Alternatives u Review Figure 62 on handout u Notice untility scores for each concept fragment and each objective (upper left corner, see Notes for meaning) u Which concept(s) is the winner?

27. 27 Comments on Notebook Assessment u None of the Notebooks received at least a Meets for TA5 even though there was evidence of much work being done u Most assessments for IA8 were meets but there were some E’s and a few NI’s

28. 28 Notebook Assessment Continued u The notebook work (TA5 & IA8) is the one body of work that can be reassessed as M or E independent of the first assessment u I will log in the best assessment received for TA5 and IA8