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Relative Placement How - To

This document is to be used with "The Relative Placement System of TNGSDC 10/94.”

 

The TNGSDC Relative Placement Tally System assumes that all judge's scores are equal; one judge should not be able to significantly alter the outcome of a contest.

 

At least five judges are required to use the relative placement scoring system. Odd numbers of judges are better than even number of judges to obtain majorities (5 out of seven is easier to resolve than four out of six). A head judge is required to break tie scores. A judge may not give tie (i.e., duplicate) scores between any two couples in the contest. For complete details, please refer to "The Relative Placement System of TNGSDC 10/94."

 

1.   Convert all raw scores to ordinals. Look at each score for a given judge, and assign places, giving the highest score first place, the second highest second place, etc., until all places for all couples are assigned for each judge.

 

Raw Scores


Scores

 

Jdg 1

Jdg 2

Jdg 3

Jdg 4

Jdg 5

Couple 1

7.0

9.0

7.5

8.8

7.55

Couple 2

5.0

8.8

7.4

8.6

7.5

Couple 3

8.0

8.7

8.8

8.7

9.7

Couple 4

6.0

8.9

7.6

8.9

9.9

Couple 5

9.9

9.1

7.8

9.0

7.0

 

Step-by-step example: Judge I

Step 1

... 2

... 3

... 4

...5

9.9= 1

8.0 = 2

7.0 = 3

6.0 = 4

5.0 = 5

Jdg 1

Jdg 1

Jdg 1

Jdg 1

Jdg 1

7.0

7.0

3

3

3

5.0

5.0

5.0

5.0

5

8.0

2

2

2

2

6.0

6.0

6.0

4

4


 

Raw scores converted to ordinals

Scores

 

Jdg 1

Jdg 2

Jdg 3

Jdg 4

Jdg 5

Couple 1

3

2

4

3

3

Couple 2

5

4

5

5

4

Couple 3

2

5

1

4

2

Couple 4

4

3

3

2

1

Couple 5

1

1

2

1

5

 

 

2.   Count all first place votes for each couple, then first through second, etc., until a majority for a place is reached. The tally columns to the right represent 1st through 1st (1 >1), 1st through 2nd (1>2), etc. The example below places couple 5 in first place since three out of five judges have them in first. Once a couple has been awarded a place, you do not need to consider their scores to place the remaining couples.

 

Scores

 

 

 

 

 

Places

 

 

 

 

 

 

Jdg 1

Jdg 2

Jdg 3

Jdg 4

Jdg 5

1>1

1>2

1>3

1>4

1>5

place

Couple 1

3

2

4

3

3

 

 

 

 

 

 

Couple 2

5

4

5

5

4

 

 

 

 

 

 

Couple 3

2

5

1

4

2

1

 

 

 

 

 

Couple 4

4

3

3

2

1

1

 

 

 

 

 

Couple 5

1

1

2

1

5

3

>

>

>

>

1st

 

 

3.   Repeat for all places, until you have ties in the number of votes. Below, second place is awarded to couple 3 - they have a majority of votes (again, three out of five) for second and above. Continuing on, counting the number of placements for third and above, we find a tie between couple 4 and couple 1.

 

 

Scores

 

 

 

 

 

Places

 

 

 

 

 

 

Jdg 1

Jdg 2

Jdg 3

Jdg 4

Jdg 5

1>1

1>2

1>3

1>4

1>5

place

Couple 1

3

2

4

3

3

 

1

4

 

 

 

Couple 2

5

4

5

5

4

 

 

 

 

 

 

Couple 3

2

5

1

4

2

1

3

>

>

>

2nd

Couple 4

4

3

3

2

1

1

2

4

 

 

 

Couple 5

1

1

2

1

5

3

>

>

>

>

1st

 

4. Resolve ties by adding the sum of placements received for the ordinals in which they

are tied. In this case, add the placements from I st through 3rd. Sums are in parenthesis.

The lower the sum, the higher they place (1st, 2nd, 3rd, 3rd beats 2nd, 3rd, 3rd, 3rd).

Award the next place to the couple tied for that ordinal.

 

 

Scores

 

 

 

 

 

Places

 

 

 

 

 

 

Jdg 1

Jdg 2

Jdg 3

Jdg 4

Jdg 5

1>1

1>2

1>3

1>4

1>5

place

Couple 1

3

2

4

3

3

 

1

4 (11)

 

 

 

Couple 2

5

4

5

5

4

 

 

 

 

 

 

Couple 3

2

5

1

4

2

1

3

>

>

>

2nd

Couple 4

4

3

3

2

1

1

2

4 (10)

 

 

 

Couple 5

1

1

2

1

5

3

>

>

>

>

1st

 

5. Continue until all places are awarded.

 

 

Scores

 

 

 

 

 

Places

 

 

 

 

 

 

Jdg 1

Jdg 2

Jdg 3

Jdg 4

Jdg 5

1>1

1>2

1>3

1>4

1>5

place

Couple 1

3

2

4

3

3

 

1

4 (11)

>

>

4th

Couple 2

5

4

5

5

4

 

 

 

2

5

5th

Couple 3

2

5

1

4

2

1

3

>

>

>

2nd

Couple 4

4

3

3

2

1

1

2

4 (10)

>

>

3rd

Couple 5

1

1

2

1

5

3

>

>

>

>

1st

 

 

 

The above examples cover most scoring situations you may come across. For more details on other tie situations, refer to the text, The Relative Placement Scoring System Rules, by Jeff Kletsky.


Addendum - Disadvantages of other scoring systems

 

·       AVERAGING RAW SCORES

Using raw scores and averaging the results is NOT recommended. It is easy for one or two judges to sway the contest in their favor. Mathematically speaking, the judge with the widest range of scores, from highest to lowest, will have the most influence on the scores. Taking the raw scores from the exercise on the previous pages, note that the results come out quite differently.

 

Raw Scores

Scores

 

 

 

 

 

Sum

Avg.

Place

RPS Placing

 

Jdg 1

Jdg 2

Jdg 3

Jdg4

Jdg 5

 

 

 

 

Couple 1

7.0

9.0

7.5

8.8

7.55

39.85

7.97

4th

4th

Couple 2

5.0

8.8

7.4

8.6

7.5

37.3

7.46

5th

5th

Couple 3

8.0

8.7

8.8

8.7

9.7

43.9

8.78

1st

2nd

Couple 4

6.0

8.9

7.6

8.9

9.9

41.3

8.26

3rd

3rd

Couple 5

9.9

9.1

7.8

9.0

7.0

42.8

8.56

2nd

1st

 

 

Judge 5 had a major influence on the scores. Judge 5 had a very wide range of scores. The single low score given to Couple 5 by Judge 5 lowered the them from first to second, despite the fact that 3 out of 5 judges had them in first place.

 

Here is another example:

At first glance, the scores seem to be relatively even.

Raw     Scores

Scores

 

 

 

 

 

Sum

Avg.

Place

 

Jdg 1

Jdg 2

Jdg 3

Jdg 4

Jdg 5

 

 

 

Couple 1

9.9

9

8

8

7

41.9

8.38

3rd

Couple 2

9.8

8.8

7.8

7.8

7.2

41.4

8.28

5th

Couple 3

9.7

8.7

7.7

8.2

7.4

41.7

8.34

4th

Couple 4

9.6

8.6

7.6

8.1

8.1

42

8.4

2nd

Couple 5

9.5

8.5

7.4

8.5

8.4

42.3

8.46

1st

 

 

Relative Placement - Majority Tally (above raw scores converted to ordinals and tallied)

 

Scores

 

 

 

 

 

Places

 

 

 

 

RPS

Ave.

 

Jdg 1

Jdg 2

Jdg 3

Jdg 4

Jdg 5

1>1

1>2

1>3

1>4

1>5

place

place

Couple 1

1

1

1

4

5

3

>

>

>

>

1st

3rd

Couple 2

2

2

2

5

4

 

3

>

>

>

2nd

5th

Couple 3

3

3

3

2

3

 

1

5

>

>

3rd

4th

Couple 4

4

4

4

3

2

 

1

2

5

>

4th

2nd

Couple 5

5

5

5

1

1

2

2

2

2

5

5th

1st

 

Once we convert the raw scores to ordinals it is easy to see how the panel as a whole has judged the contest. Using the raw scores would have resulted in a disaster! A fifth place couple winning first, a second getting fifth, etc.! This occurred because most of the judges had scores within only a half point range while Judge 5 had a scoring range of a point and a half. Normally this is not necessarily bad by itself; however, in this case, it was enough to sway the scores...


·           USING SUMS OF ORDINALS INSTEAD OF MAJORITY TALLY

 

Simple sums of ordinals are NOT recommended.

 

Using the scores from the previous example (the one used to illustrate the problems with point scoring,) we see that using placement totals have a few problems...

 

Scores

 

 

 

 

 

Places

 

 

 

 

RPS

Place

 

 

Jdg 1

Jdg 2

Jdg 3

Jdg 4

Jdg 5

1>1

1>2

1>3

1>4

1>5

place

Totals

Place

Couple 1

1

1

1

4

5

3

>

>

>

>

1st

12

1st

Couple 2

2

2

2

5

4

 

3

>

>

>

2nd

15

3rd

Couple 3

3

3

3

2

3

 

1

5

>

>

3rd

14

2nd

Couple 4

4

4

4

3

2

 

1

2

5

>

4th

17

tie

Couple 5

5

5

5

1

1

2

2

2

2

5

5th

17

tie

 

Taking a sum of the placements has given us a different placement result for couples 2 and 3. Note that the majority of judges clearly had couple 2 place higher than couple 3. But if we use totals, the final placements would be reversed.

 

There is also a tie for 4th place. Looking at the scores, anyone would clearly break the tie by seeing that couple 4 had more judges placing them higher than couple 5, therefore they should get 4th place. When we start to use that logic, we might as well use RPS for the whole contest anyway...

 

Still not convinced? In the example below, a clear majority has awarded one couple first, second and third places. Taking a sum instead of looking for majorities may result in placement that disagrees with the majority of the judging panel. Looking for majorities eliminates the possibility of one or a minority of judges (in this case, judge four and five) from "taking over" the judging for the contest.

 

Scores

 

 

 

 

 

 

Sums

Places

 

 

 

 

RPS

 

Jdg 1

Jdg 2

Jdg 3

Jdg 4

Jdg 5

Sums

place

1>1

1>2

1>3

1>4

1>5

place

Couple 1

1

1

1

3

5

11

2nd

3

>

>

>

>

1st

Couple 2

2

2

2

2

2

10

1st

 

5

>

>

>

2nd

Couple 3

3

3

3

5

3

17

4th

 

 

4

>

>

3rd

Couple 4

4

4

4

1

1

14

3rd

2

2

2

5

>

4th

Couple 5

5

5

5

4

4

23

5th

 

 

 

2

5

5th

 

In the above example, three out of five judges clearly had couple 1 in first; yet using sums would mean that couple 1 would get 2nd place, because judge 5 scored them in fifth place. Using sums, couple 4 would be awarded 3rd, despite the fact that couple 3 had four votes out of five for them in third place. Using the columns on the right, you can see that the RPS majority tally system eliminates the tendency of one judge to sway the results of a contest.

 

Also, mathematically speaking, the larger the field (more contestants) the more potential there exists for numerical variation, in which using sums would result in even wilder results. A judge could easily “bury” a contestant/couple by giving them the lowest score. Using the sums means that the worse placement counts more.