The
Palm OBO-2000
calculator The
Palm OBO-2000
calculator
Ice-skating ranking obey to some well-defined rules. But those rules aren't easy to understand. This was be complicated when ISU (International Skating Union) introduce new OBO (One by One) rules in 1998, and when they was modified in 2000.
There are some great principles allowing understanding ranking systems. Calculating scores will be a difficult task and using computer help us.
Ice skating ranking follows 4 steps described below:
Odd number of judges defines each their own competitor positions list. To do that they give to each competitor a technical mark and an artistic mark. Some rules about the scoring are defined about the performed elements and penalty points. Meanwhile judging is subjective and follows the judge experience.
Ranking is based on the sum of those two notes. In case of tie, one of those notes (contest type dependent) is preponderant.
There is no relationship between judge's marks. Only the rank given by each judge is relevant.
Example: (short program, Technical preponderant)
|
Candidate : |
Ann |
Britney |
Celia |
Donna |
Ellen |
Fanny |
| Technical : |
5.1(+) |
5.7 |
5.6 |
5.0(-) |
5.3 |
5.6 |
| Artistic : |
5.1 |
5.6 |
5.6 |
5.2 |
5.4 |
5.6 |
| Total : |
10.2 |
11.3 |
11.2 |
10.2 |
10.7 |
11.2 |
| Rang : |
5 |
1 |
2(tie) |
6 |
4 |
2(tie) |
It is important to remember that the note values by them self aren't useful.
Example:
If your skater obtain those notes,
|
Judge |
Juge1 |
Juge2 |
Juge3 |
| Technical |
5.1 |
5.2 |
5.0 |
| Artistic |
5.2 |
5.1 |
4.9 |
| Total |
10.3 |
10.3 |
7.9 |
You protest about the third judge mark. Meanwhile some future competitor should reversal your opinion:
|
My candidate |
Juge1 |
Juge2 |
Juge3 |
| Technical |
5.1 |
5.2 |
5.0 |
| Artistic |
5.2 |
5.1 |
4.9 |
| Total |
10.3 |
10.3 |
9.9 |
| RANK |
2 |
2 |
1 ß |
| An other |
Juge1 |
Juge2 |
Juge3 |
| Technical |
5.2 |
5.2 |
4.9 |
| Artistic |
5.1 |
5.2 |
4.8 |
| Total |
10.3 |
10.4 |
9.7 |
| RANK |
1 |
1 |
2 |
There is a full competition example (short program, Technical preponderant) used below for the explains:
|
Names : |
|
J1 |
J2 |
J3 |
J4 |
J5 |
J6 |
J7 |
| Ann |
Technical |
4.8 |
5.1 |
5.0 |
5.1 |
5.1 |
4.9 |
4.9 |
|
|
Artistic |
5.2 |
5.3 |
5.1 |
5.1 |
5.1 |
5.1 |
5.1 |
|
|
Total |
10.0 |
10.4 |
10.1 |
10.2 |
10.2 |
10.0 |
10.0 |
|
|
Rank |
6 |
5 |
6 |
5 |
5 |
6 |
6 |
| Britney |
Technical |
5.5 |
5.5 |
5.4 |
5.5 |
5.7 |
5.2 |
5.4 |
|
|
Artistic |
5.4 |
5.5 |
5.4 |
5.4 |
5.6 |
5.3 |
5.4 |
|
|
Total |
10.9 |
11.0 |
10.8 |
10.9 |
11.3 |
10.5 |
10.8 |
|
|
Rank |
3 |
2 |
5 |
2 |
1 |
5 |
3 |
| Celia |
Technical |
5.7 |
5.6 |
5.6 |
5.5 |
5.6 |
5.5 |
5.4 |
|
|
Artistic |
5.8 |
5.7 |
5.7 |
5.7 |
5.6 |
5.6 |
5.6 |
|
|
Total |
11.5 |
11.3 |
11.3 |
11.2 |
11.2 |
11.1 |
11.0 |
|
|
Rank |
1 |
1 |
1 |
1 |
2 |
1 |
1 |
| Donna |
Technical |
5.4 |
4.9 |
5.4 |
4.9 |
5.0 |
5.3 |
5.4 |
|
|
Artistic |
5.4 |
5.2 |
5.5 |
4.9 |
5.2 |
5.5 |
5.5 |
|
|
Total |
10.8 |
10.1 |
10.9 |
9.8 |
10.2 |
10.8 |
10.9 |
|
|
Rank |
4 |
6 |
2 |
6 |
6 |
3 |
2 |
| Ellen |
Technical |
5.6 |
5.2 |
5.4 |
5.2 |
5.3 |
5.4 |
5.4 |
|
|
Artistic |
5.5 |
5.2 |
5.5 |
5.3 |
5.4 |
5.6 |
5.4 |
|
|
Total |
11.1 |
10.4 |
10.9 |
10.5 |
10.7 |
11.0 |
10.8 |
|
|
Rank |
2 |
4 |
2 |
4 |
4 |
2 |
3 |
| Fanny |
Technical |
4.6 |
5.2 |
5.2 |
5.1 |
5.5 |
5.1 |
5.2 |
|
|
Artistic |
5.5 |
5.5 |
5.7 |
5.6 |
5.7 |
5.5 |
5.5 |
|
|
Total |
10.1 |
10.7 |
10.9 |
10.7 |
11.2 |
10.6 |
10.7 |
|
|
Rank |
5 |
3 |
4 |
3 |
3 |
4 |
5 |
Judge by judge ranking (top)
Only that part of the table is useful for the ranking determination:
|
|
J1 |
J2 |
J3 |
J4 |
J5 |
J6 |
J7 |
| Ann |
6 |
5 |
6 |
5 |
5 |
6 |
6 |
| Britney |
3 |
2 |
5 |
2 |
1 |
5 |
3 |
| Celia |
1 |
1 |
1 |
1 |
2 |
1 |
1 |
| Donna |
4 |
6 |
2 |
6 |
6 |
3 |
2 |
| Ellen |
2 |
4 |
2 |
4 |
4 |
2 |
3 |
| Fanny |
5 |
3 |
4 |
3 |
3 |
4 |
5 |
Standard placement determination (top)
Until 1998, placement determination try to find the competitor with a maximum of first places (but more than half the judge number), next we try to find the competitor with maximum of first and second places, next 1st, 2nd and 3rst,...
In case of tie, the sum of ranks given by the used judges decides between us.
Some more ties are decided between using sum off all ranks, then with the sum of the notes.
We obtain those ranks:
This placement determination should involve some mismatch using ambiguous grouped rank sequence and more important should involve swapping of two competitors by a subsequent competitor partially scored between them.
The OBO-1998 placement determination (top)
For those raisons, the ISU determine in 1998 a new method called OBO (One By One) witch compare all competitor to all others. For each win, they obtain a WIN point. For tie determination, we sum also all the judge by judge win into the "judge in favour" JIF point.
In case of tie, we give one WIN or one JIF to each competitor.
For example:
Ellen with Fanny give 1 WIN for Ellen (4 judges on 7), 4 JIF for Ellen and 3 JIF for Fanny.
Ellen with Donna with 1 WIN for Ellen (5 / 7), 6 JIF for Ellen and 2 JIF for Donna.
Ellen with Britney with 1 WIN for both (3 judges on 7 both), 4 JIF for both.
The OBO-1998 full tables are:
| WIN |
A |
B |
C |
D |
E |
F |
total |
|
JIF |
A |
B |
C |
D |
E |
F |
total |
| A: |
-- |
0 |
0 |
0 |
0 |
0 |
0 |
|
A: |
-- |
0 |
0 |
3 |
0 |
0 |
3 |
| B: |
1 |
-- |
0 |
1 |
"1" |
1 |
4 |
|
B: |
7 |
-- |
1 |
4 |
"4" |
5 |
21 |
| C: |
1 |
1 |
-- |
1 |
1 |
1 |
5 |
|
C: |
7 |
6 |
-- |
7 |
7 |
7 |
34 |
| D: |
1 |
0 |
0 |
-- |
0 |
1 |
2 |
|
D: |
4 |
3 |
0 |
-- |
"2" |
4 |
13 |
| E: |
1 |
"1" |
0 |
1 |
-- |
1 |
4 |
|
E: |
7 |
"4" |
0 |
"6" |
-- |
4 |
21 |
| F: |
1 |
0 |
0 |
0 |
0 |
-- |
1 |
|
F: |
7 |
2 |
0 |
3 |
3 |
-- |
15 |
We obtain those ranks:
This method doesn't suppress all swapping effect, they are more limited (mainly with WIN tie). But the competitors with tie notes are favoured again the others.
The OBO-2000 placement determination (top)
For those raisons, the ISU modify in 2000 the OBO method always comparing all competitors together.
For each win, they obtain 2 "Comparative Point" (COP). For tie determination, we look also to all the judge by judge win, given 2 "Points in Favour" (PIF) for each win.
In case of tie, we give only one COP or only one PIF to each competitor.
For example:
Ellen with Fanny give 2 COP for Ellen (4 judges on 7), 8 PIF for Ellen and 6 PIF for Fanny.
Ellen with Britney with 1 COP for both (3 judges on 7 both), 7 PIF for both.
The OBO-2000 full tables are:
| COP |
A |
B |
C |
D |
E |
F |
total |
|
PIF |
A |
B |
C |
D |
E |
F |
total |
| A: |
-- |
0 |
0 |
0 |
0 |
0 |
0 |
|
A: |
-- |
0 |
0 |
6 |
0 |
0 |
6 |
| B: |
2 |
-- |
0 |
2 |
"1" |
2 |
7 |
|
B: |
14 |
-- |
2 |
8 |
"7" |
10 |
41 |
| C: |
2 |
2 |
-- |
2 |
2 |
2 |
10 |
|
C: |
14 |
12 |
-- |
14 |
14 |
14 |
68 |
| D: |
2 |
0 |
0 |
-- |
0 |
2 |
4 |
|
D: |
8 |
6 |
0 |
-- |
"3" |
8 |
25 |
| E: |
2 |
"1" |
0 |
2 |
-- |
2 |
7 |
|
E: |
14 |
"7" |
0 |
"11" |
-- |
8 |
40 |
| F: |
2 |
0 |
0 |
0 |
0 |
-- |
2 |
|
F: |
14 |
4 |
0 |
6 |
6 |
-- |
30 |
We obtain those ranks:
Method comparison (top)
We obtain near the same result in each case. OBO-1998 involves some tie injustice. If judges are in accordance, all the results are the same. But if they are some big difference between judges those three methods should give some different placements.
From 1st september 2000,official method is OBO-2000, but during transition some competition may still be computed with some old OBO-1998 programs!
If a competition have more than one part ("short program" and "free program" or take care about qualification), we assign a part factor (for example 0.5 and 1.0). We multiply rank on each part by them part factor and sum it. Final placement is according to lower total. Tie is usually decided between using the "free program".
Conclusion (top)
As this article show, using a computer is mandatory when the number of judges or competitors increase. The authors wrote an OBO calculator for Palm organiser. It is useful and easy to have in hand during competition. You will find all information about it on the WEB at www.a2m2.ch/fred/skating.
However, even with a computer, you need to know exactly all the contest parameters:
Even with all right parameters, only the official result sheet signed by the main judge will apply.
fred@a2m2.ch 28/12/2000.