Cox-Sprague Scoring System

 


Shields Fleet One and other Yacht Racing Association of Long Island Sound (YRALIS) classes use the Low-Point scoring system for individual events, but use the Cox-Sprague scoring system for the season rankings. YRLIS also uses the Cox-Sprague system for selecting boats from among all the classes for the season trophies.

The Cox-Sprague scoring system is useful for scoring a long series of races where the number of boats varies from race to race. Races with a larger number of competitors get higher weighting.

The Cox-Sprague percentage score for a race series is the total number of points the boat earned in the series divided by the total number of points it could have earned by placing first in every race it started.

The points are awarded using the table below. In each race the number of starters determines the column to be used. Each boat is credited with the number of points indicated for her finishing place. The boats that do not finish (DNF), retire (RET) or are disqualified (DSQ) get points for the place equal to the number of starters plus one. Boats that do not start (DNS) or do not compete (DNC) are not scored. Since each boat is scored only in the races in which it participates, this gives each boat a chance to compete for the series title without the need to enter every race. A boat needs to start a minimum number of races, typically 40% to 60% of all races in the series, to be eligible for series prizes.

For example, if a boat places 2nd among 5 boats in one race and 3rd among 4 in another, the boat earns 46 out of a possible 52 in the first race and 33 out of a possible 43 in the second. Its percentage for the two races it sailed is (46+33)/(52+43) = 79/95 = 83.16%.

A boat that wins every race it enters earns a series percentage score of 100%. A boat that finishes last in a race receives percentage scores ranging from 59% (=59/100) in a 20 boat race to 67.7% (=21/31) in a three boat race. The original Cox-Sprague table awarded 40% to a boat finishing second in a two boat race. The table below has been modified to award 70% for the second place finish in a two boat race and 50% for DNF or DSQ in a two boat race for consistency with the rest of the table.

Cox-Sprague Table

Place                 Number of Starters
         2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20

 1      10 31 43 52 60 66 72 76 80 84 87 90 92 94 96 97 98 99 100
 2       7 25 37 46 54 60 66 70 74 78 81 84 86 88 90 91 92 93 94
 3       5 21 33 42 50 56 62 66 70 74 77 80 82 84 86 87 88 89 90
 4       . 17 29 38 46 52 58 62 66 70 73 76 78 80 82 83 84 85 86
 5       .  . 26 35 43 49 55 59 63 67 70 73 75 77 79 80 81 82 83
 6       .  .  . 32 40 46 52 56 60 64 67 70 72 74 76 77 78 79 80
 7       .  .  .  . 38 44 50 54 58 62 65 68 70 72 74 75 76 77 78
 8       .  .  .  .  . 42 48 52 56 60 63 66 68 70 72 73 74 75 76
 9       .  .  .  .  .  . 46 50 54 58 61 64 66 68 70 71 72 73 74
10       .  .  .  .  .  .  . 48 52 56 59 62 64 66 68 69 70 71 72
11       .  .  .  .  .  .  .  . 50 54 57 60 62 64 66 67 68 69 70
12       .  .  .  .  .  .  .  .  . 52 55 58 60 62 64 65 66 67 68
13       .  .  .  .  .  .  .  .  .  . 53 56 58 60 62 63 64 65 66
14       .  .  .  .  .  .  .  .  .  .  . 55 57 59 61 62 63 64 65
15       .  .  .  .  .  .  .  .  .  .  .  . 56 58 60 61 62 63 64
16       .  .  .  .  .  .  .  .  .  .  .  .  . 57 59 60 61 62 63
17       .  .  .  .  .  .  .  .  .  .  .  .  .  . 58 59 60 61 62
18       .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 58 59 60 61
19       .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 58 59 60
20       .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 58 59
21       .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 58

Cox-Sprague Calculator

An Excel based Cox-Sprague Calculator computes Cox-Sprague percentages for each boat given the boat's results, number of starters in each race and the number of discards. The calculator spreadsheet contains additional examples, detailed documentation and a template for scoring of a race series.

Average-Place Scoring System

The Average-Place scoring system proposed below is a simpler alternative to the Cox-Sprague system.

The Average-Place score for a race series is the average of the boat's finishing places in all the races it started.
DNF and DSQ are scored as number of starters plus one. DNS and DNC are not scored. The lowest score wins.

When the number of participants does not vary significantly from race to race, the Average-Place system returns rankings that are very similar to the rankings produced by the Cox-Sprague system.

An Excel based Average-Place Calculator computes Average-Place scores for each boat given the boat's results, number of starters in each race and the number of discards. The calculator spreadsheet contains a template for scoring of a race series.