Pairwise comparison of items and environment

Energy and Environment

1. https://indrajeetpatil.github.io/pairwiseComparisons/

2. Pairwise comparison Pairwise comparison is a tool to rank a set of decision-making criteria and rate the criteria on a relative scale of importance, Making decisions requires comparing alternatives with respect to a set of criteria . If there are more than two criteria, determining which criteria are more important can itself be a serious problem. One would like to be able to rank the criteria in order of importance, and to assign to the criteria some relative ranking indicating the degree of importance of each criterion with respect to the other criteria. Pairwise comparison is one way to determine how to evaluate alternatives by providing an easy and reliable means to rate and rank decision-making criteria. It is often used to assign weights to design criteria in concept evaluation. https://deseng.ryerson.ca/dokuwiki/design:pairwise_comparison#:~:text=Pairwise%20comparison%20is%20one%20way,design%20criteria%20in%20concept%20evaluation

3. Pairwise comparison stages Pairwise comparison is implemented in two stages: determine qualitatively which criteria are more important – i.e. establish a rank order of the criteria, and assign to each criterion a quantitative weight such that the qualitative rank order is satisfied.

4. The pairwise comparison method Identify the criteria to be ranked. Arrange the criteria in a square matrix . Each cell in the matrix corresponds to a comparison of a pair of items (hence the name “pairwise comparison”). The cells will contain the item that is considered the most important of the pair. Obviously, we only need one triangle of the matrix, because comparing A to B is the same as comparing B to A. Since the rows and columns contain exactly the same things in the same order, one triangle of the matrix will contain just a mirror image of the other. Furthermore, the diagonal of the matrix is irrelevant – it simply doesn't make sense to consider how important one criterion is with respect to itself! Compare pairs of criteria across rows For each row, consider the criterion in the row with respect to each criterion in the rest of that row. The first comparison in our matrix is functionality versus durability. Which is more important? Discuss this in your teams and reach a consensus to that question. In the corresponding cell of the matrix, put the letter of the criterion that is most important. Do not consider any other criteria beyond the two that you are comparing. Then go on to the next pair (in our example, functionality versus quality). If we really, really think that two criteria are of equal importance, then we put both letters in the corresponding cell. Note that the individual comparisons are pairwise – we completely ignore the other criteria. Say we decide that functionality is more important than durability. We would then put a A into cell (2, 4) of the matrix. We continue doing this till all the empty cells have been filled. Notice the double letters in some cells. We have used this convention to indicate that the two criteria being compared are of equal importance; that is, you just could not decide which of the two criteria was more important.This step must be documented to provide justifications for your decisions. Ideally, every decision you make in constructing the PWC chart needs to be justified. In the example above, that's 36 decisions - one for each pair that you compared. Justifications would be given with respect to your requirements and framed with respect to your product strategy, user groups, and personas. You can document this by simply listing each pair of PCs you compared and giving a short (1-4 sentences) justification - the shorter, the better - referencing specific elements of your PSS and PRS as required Create the ranking Assign weights There are two basic constraints on how we assign the weights. The total of all the weights must be 100%. The weights must obey the relative ranking given by the pairwise comparison.

5. Pairwise Comparison Charts (PCC): Setting Up and Running Them for a water bottle example https://www.youtube.com/watch?v=orrQFHKlocs Is a tool used to rank design objectives

6. Example: drinking water bottle Use a Pairwise Comparison Chart (PCC) to compare, rank and reflect on objectives (criteria) for a water bottle. (Hint: assume selected objectives to be ease of use, maintain temperature , durability, cost , and aesthetics considerations ).

7. Place dash for identical objectives

8. Use 1 as the high score and as the low score Importance Score

9. Use 1 in Row of Most Important Factor Use 0 in Row of Least Important Factor

10. Problems with PCC : drinking water bottle FOUR Types of Problems 1) Error: Tie in Total 2) Disagreement among Team 3) Constraint instead of Objective 4) Real Tie: When two factors are equally important

11. 2) Disagreement among Team In order to solve such problems, you must conduct in-depth survey to understand the design demand of the client or public while making the policy decision.

12. 4) Actual Tie:

13. CONCLUSION: After finishing the PCC the design team or policy makers can move on to their design their policy/products to meet the challenges

14. Using Pairwise Comparison Find the Winner of Election: No. of Voter 19 12 11 9 3 1 st Choice D C B A A 2 nd Choice A A A D C 3 rd Choice B B D C D 4 th Choice C D C B B

15. Using Pairwise Comparison Find the Winner of Election: No. of Voter 10 8 7 5 4 1 st Choice B C A D A 2 nd Choice A A B A D 3 rd Choice D B C B C 4 th Choice C D D C B

16. Using Pairwise Comparison Find the Winner of Election: No. of Voter 17 11 7 3 1 1 st Choice D A A C B 2 nd Choice A D B A A 3 rd Choice B C C B C 4 th Choice C B D D D

17. Using Pairwise Comparison Find the Winner of Election: No. of Voter 14 10 8 5 1 1 st Choice D A D C A 2 nd Choice A B B A C 3 rd Choice B C A B B 4 th Choice C D C D D

18. Using Pairwise Comparison Find the Winner of Election: No. of Voter 14 10 8 4 1 1 st Choice A C D B C 2 nd Choice B B C D D 3 rd Choice C D B C B 4 th Choice D A A A A

19. C is the WINNER

20. Independence of Irrelevant Alternatives Criterion According to this criterion a factor that would otherwise not be the popular choice of the masses, holds irrelevant features that affect the result of mass selection. In the above example, a candidate C, who would not have won the election has dropped-out thus leading to change in WINNING Candidate. Thus, the criterion states that A criterion that says that a candidate who would otherwise win an election should not lose the election merely because one of the losing candidates withdraws from the race.

21. Using Pairwise Comparison Find the Winner of Election – EXAMPLE 2: No. of Voter 2 6 4 1 1 4 4 1 st Choice A B B C C D E 2 nd Choice D A A B D A C 3 rd Choice C C D A A E D 4 th Choice B D E D B C B 5 th Choice E E C E E B A

22. No. of Voter 2 6 4 1 1 4 4 1 st Choice A B B C C D E 2 nd Choice D A A B D A C 3 rd Choice C C D A A E D 4 th Choice B D E D B C B 5 th Choice E E C E E B A A is the WINNER

23. No. of Voter 2 6 4 1 1 4 4 1 st Choice A B B C C D E 2 nd Choice D A A B D A C 3 rd Choice C C D A A E D 4 th Choice B D E D B C B 5 th Choice E E C E E B A Candidate C has dropped out. No. of Voter 2 6 4 1 1 4 4 1 st Choice A B B B D D E 2 nd Choice D A A A A A D 3 rd Choice B D D D B E B 4 th Choice E E E E E B A

24. No. of Voter 2 6 4 1 1 4 4 1 st Choice A B B B D D E 2 nd Choice D A A A A A D 3 rd Choice B D D D B E B 4 th Choice E E E E E B A B is the WINNER Independence of Irrelevant Alternatives Criterion

25. SOLUTION: EXAMPLE PROBLEM https://www.youtube.com/watch?v=R1m3WJ6P8H8&list=TLPQMDQwMjIwMjLm6wCaSo6DbQ&index=3

26. The analytic hierarchy process AHP Priority Calculator https://bpmsg.com/ahp/ahp- calc.php?n=5&t=AHP+priorities&c[0]=ease+of+use&c[1]=maintain+tem perature&c[2]=durability&c[3]=cost&c[4]=aesthetics +