The Flaw in the Polls

© Copyright 2006, Paul Kislanko

Rnk Team Borda Maj Cnt #1
1 Ohio State 5339 2 34 19
2 LSU 5185 6 29
3 Southern California 5121 2 27 17
4 Notre Dame 5085 5 26 2
5 Auburn 5070 8 27 1
6 Georgia 4967 11 28
7 Florida 4802 10 26 2
8 West Virginia 4757 11 27
9 Texas 4719 5 24 2
10 Oregon 4690 12 27
11 Louisville 4657 14 27
12 Virginia Tech 4598 9 24
13 Michigan 4412 14 25
14 Oklahoma 4076 17 24
15 Texas Tech 3937 19 24
16 TCU 3642 22 27 1
17 Boston College 3499 19 25
18 Florida St 3318 20 25
19 Boise St 3281 22 25
20 Iowa 3038 21 24
21 Nebraska 2929 22 25
22 Wisconsin 2800 23 24
23 Penn State 2777 24 25
24 California 2719 24 25
25 UCLA 2710 24 24
Rnk Team Borda Maj Cnt #1
26 Tennessee 2437 25 24 1
27 Miami-Florida 2150    
28 Pittsburgh 2008    
29 Alabama 1934    
30 Clemson 1586    
31 Arizona St 1278    
32 Rutgers 724    
33 Oklahoma St 640    
34 Missouri 622    
35 Indiana 548    
36 Texas A&M 505    
37 Georgia Tech 499    
38 Kansas St 437 -- -- 1
39 BYU 399    
40 Iowa State 391    
40 Washington St 391    
42 Maryland 389    
43 Air Force 306    
44 Houston 201    
44 Navy 201    
46 Tulsa 196    
47 Purdue 192    
48 Nevada 188    
49 Connecticut 109    
Rnk Team Borda Maj Cnt #1
50 Fresno St 102    
51 UTEP 99    
51 Utah 99    
53 Minnesota 98    
54 Wake Forest 97    
55 Oregon St 97    
55 South Carolina 97    
55 Hawaii 97    
58 Michigan St 96    
58 Arkansas St 96    
60 Arkansas 95    
60 Akron 95    
62 Virginia 94    
62 Kansas 94    

Actually, it's not the polls themselves, its the way the votes are counted.

There's a reason the Borda count method (equivalent to the 25 pts for first, 24 for second, and so on) is not used in any real election.

Here's a good example. I took the 46 computer rankings from the Football Ranking Comparison Page and counted the "votes" using Borda. I used 118 points for 1st, 117 for second, etc. just so you can tell in the "others receiving votes" category what the ranks were (a team with 99 points can only be one vote for #20, not 6 votes for #25). To simulate the human polls I truncated the "ballots" at #25.

Right at the top there's an "error" - LSU is #2 even though only three of the 46 ballots had them ranked that highly. USC is third even though 27 of the 46 ballots had them no worse than second, and 36 had them ranked higher than LSU.

Maj is the best rank for which 24 or more of the 46 agreed the team should be at least that high. Cnt is how many did.

The problem is that, like average rank, Borda can be unduly influenced by "outliers." A much better method would be to order the teams by the majority rank (equivalent to the median rank if every voter ranks the team.) When there's a tie (many teams can have the same median rank) use the count for that rank or better. If there's still a tie, use Borda to only order teams with the same majority rank.

Compare the ranking to the right with the results using this technique (which is known as the Bucklin method.) Here I've only included teams that were listed on a majority of ballots, since the remainder would be the same either way.

Rnk Team Borda Maj Cnt #1
1 Ohio State 5339 2 34 19
2 Southern California 5121 2 27 17
3 Notre Dame 5085 5 26 2
4 Texas 4719 5 24 2
5 LSU 5185 6 29
6 Auburn 5070 8 27 1
7 Virginia Tech 4598 9 24
8 Florida 4802 10 26 2
9 Georgia 4967 11 28
10 West Virginia 4757 11 27
11 Oregon 4690 12 27
12 Louisville 4657 14 27
13 Michigan 4412 14 25
14 Oklahoma 4076 17 24
15 Boston College 3499 19 25
16 Texas Tech 3937 19 24
17 Florida St 3318 20 25
18 Iowa 3038 21 24
19 TCU 3642 22 27 1
20 Boise St 3281 22 25
21 Nebraska 2929 22 25
22 Wisconsin 2800 23 24
23 Penn State 2777 24 25
24 California 2719 24 25
25 UCLA 2710 24 24
26 Tennessee 2437 25 24 1

Imagine the outcry if at the end of the season the polls came out this way? Oh wait, don't bother, it's already happend. That's why the Associated Press no longer participates and Texas got to play in a Rose Bowl. But imagine if the same thing had happened between #2 and #3 instead of #4 and #5.

The BCS changed its formula after their was an outcry because USC finished third in the BCS standings but #1 in the Associated Press poll after LSU beat Oklahoma in the championship game. The new formula made it just about impossible for there to be a disagreement between the AP and BCS.

The should-have-been expected result actually happened in 2004: a massive email campaign caused enough AP voters to switch their votes so that Texas got an automatic bid over California, the only team to beat the AP's final #1 that year. That could have only happened because Borda is so easily manipulated.

The ensuing uproar caused the AP to withdraw from the process, and the response by the BCS was not to correct the real problem but to just form a replacement poll. In 2005 there was no controversy, but it wasn't because the BCS champion was the same as the AP #1, it was just that there was only one undefeated team after the bowls and everybody had it #1.

Using a flawed voting system was never an issue as long as the polls were only used as originally intended - pick a #1 (Borda is for "single-winner elections", not a "top 25") and provide some entertainment for fans on a non-gameday. Once they became the determining factor for who would get A Whole Pile of Money, it was inevitable that the weaknesses in the system would eventually be exploited.

The formula should be fixed - really fixed, not just bandaged. An appropriate formula would:

  • give at least equal weight to the computers, which can't be affected by public pressure
  • use only the Harris Poll, since the coaches have a severe conflict of interest
  • and count the votes using Bucklin, where it takes a majority of the voters to "game the system"

    It's ironic that the AP voters helped create such a big problem they had to leave the process. The computers were de-emphasized mainly because "we don't know how they work." Fans went along with that, but 2004 made clear that both the media and typical fans know so little about how the polls work that they trust them.

    I don't know when, but some day the situation in this real-data example will happen with the BCS and we'll have the "wrong" participants in a BCS bowl again.

    On a Related Note

    Much has been made of the "lack of transparency" in the polls and usually people only talk about making the ballots public as a solution. That certainly is not a desirable solution - we want the voters watching football games not dealing with email from angry fans. Nor is it necessary.

    In order to understand why a poll came out as it did all we need is a count of the number of votes for each rank. Publishing just the number of votes for #1 was enough when the only question was "who do they think is #1?", but in the BCS it matters who is #2 (or 12, or 16). So a report like the following should be sufficient.

    Maj Cnt Borda Team #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 #20 #21 #22 #23 #24 #25
    2 34 5339 Ohio State 19 15 2 3 3 1             1   1       1          
    2 27 5121 Southern California 17 10 9 1 2 1 3     1                            
    5 26 5085 Notre Dame 2 10 5 5 4 2 3 1 5 3 2   1           1       1  
    5 24 4719 Texas 2 3 8 7 4 3 1 1 1 1 3   3 3   1 1              
    6 29 5185 LSU   3 5 9 6 6 5 2 5 1 1 1           1 1          
    8 27 5070 Auburn 1 1 3 2 8 1 5 6 1 5 2 1 2 2 2   1     2 1      
    9 24 4598 Virginia Tech     4 5   5 4 2 4 3 1 3 3   3     2 1   2      
    10 26 4802 Florida 2     4 1 3 1 7 5 3 2 4 2 2 4 1 2       1      
    11 28 4967 Georgia   1   2 3 3 6 3 1 4 5 2 3   3 4 1     2 2   1  
    11 27 4757 West Virginia     3   4 4 2 2 2 2 8 1 3 3 2 1 3 2 1           1
    12 27 4690 Oregon         3 2 3 1 6 4 4 4 3 3   1 2   2 2   1   2 1
    14 27 4657 Louisville   1 2 2 2   1 3 3 2 2 4 1 4 1   3 3 1 2 3 1 1 1 1
    14 25 4412 Michigan           1 1 2 1 2 3 3 6 6 6 2   3 3 1 1   1  
    17 24 4076 Oklahoma     1 3 1 2 2 2 3   1 2 1 2   2 2   1 4 1 3   2 4
    19 25 3499 Boston College         2 1 1   1 1 1 3 1 1 4 1 2 2 4   2   3 2 2
    19 24 3937 Texas Tech                   2   1 3 3 1 2 5 5 2 3 3 4 1 3 1
    20 25 3318 Florida St           2 3 1 1 3 1 2   1 1 1 1 1 3 4 2 1 3   1
    21 24 3038 Iowa               1         1 1 2 9 3 3 1 2 1 2 3   1
    22 27 3642 TCU 1         2       2 1 1   2 1 1 4 3 2   2 5 3 4 2
    22 25 3281 Boise St         1   3 1   1   2   2 6 1 2 1 1 1 1 2 2 2 3
    22 25 2929 Nebraska       1           1   1   3 2 2 1 3 3 3 3 2 1 1 2
    23 24 2800 Wisconsin               1       1   1 1 3 3 3 2 2 2 2 3 3 1
    24 25 2777 Penn State       1   1   3     3 1 1 1   2 2   2 3   1 2 2 2
    24 25 2719 California               1       1 3   1 5 3   2 1 1 3 2 2 2
    24 24 2710 UCLA       1           2 1   1 1     1 3 2 3 4 3 1 1 3
    Maj Cnt Borda Team #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 #20 #21 #22 #23 #24 #25
    25 24 2437 Tennessee 1         1   1 2   1         3   1 1 2 3 3 1 2 2
                                                           
        2150 Miami-Florida           1 1   1 1     2 2 1   1 2 2 1 1 2   3
        2008 Pittsburgh   1 3     1   2 1 1 1       1   1   1 1     3   2
        1934 Alabama               2 1 1   2 1         1 4 1 1   1 3 1
        1586 Clemson                 1         2 1     2 2   1   1 2 4
        1278 Arizona St                       2         1       3 1 2 3 1
        724 Rutgers                 1   1 1 1       1           1 1
        640 Oklahoma St             1 1     1   1 1             1      
        622 Missouri         1             1       2     1         1
        548 Indiana         2 2                                     1
        505 Texas A&M     1                                 2   1     1
        499 Georgia Tech                               1 1 1       1 1  
        437 Kansas St 1 1                       1               1    
        399 BYU                         1             1 1   1  
        391 Iowa State                       1                       2 1
        391 Washington St                                   1     1 1   1
        389 Maryland                                   1         3  
        306 Air Force                       1       1             1  
        201 Houston                             1             1    
        201 Navy                         1                     1
        196 Tulsa                                         2      
        192 Purdue                                         1       1
        188 Nevada                                                 2
        109 Connecticut                   1                            
    Maj Cnt Borda Team #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 #20 #21 #22 #23 #24 #25
        102 Fresno St                                 1              
        99 UTEP                                       1        
        99 Utah                                       1        
        98 Minnesota                                         1      
        97 Wake Forest                                           1    
        97 Oregon St                                           1    
        97 South Carolina                                           1    
        97 Hawaii                                           1    
        96 Michigan St                                             1  
        96 Arkansas St                                             1  
        95 Arkansas                                               1
        95 Akron                                               1
        94 Virginia                                                 1
        94 Kansas                                                 1
        94 New Mexico                                                 1