The Selection Process:
The selection process for teams to compete in the NESSA Team Racing Championship (Mark Trophy) is based upon a ranking system that has been developed and improved upon over several years. The current version, Plan L, combines a computer ranking with a coaches’ poll.
The Computer Rating System:
The current computer rating, in use since 2006 with one update, is based upon the following three factors: overall winning percentage, strength of schedule, and winning percentage against Top 20 teams, each expressed as 1000 times the decimal fraction. Once the computer rating is determined for all the teams in NESSA, they are given an ordinal computer ranking. The foundation of this system is that there are no preconceived or a priori assumptions and that all the computations are based on actual on-the-water results for the current season.
Overall Winning Percentage (WP):
The fundamental metric of a team’s success is their overall winning percentage (WP), calculated as the fraction of wins divided by the number of team racing meets. For a team with a record of 9 wins and 3 losses, their WP would be 750. While the WP is a good place to start, it can be distorted by the quality of competition. In other words, a team might have a great record against weak opponents while another may have a mediocre record against highly competitive opponents and the WP alone would not adequately represent this potential difference in achievement. To augment the WP, two other factors are also used: the strength of schedule (SOS) and the winning percentage against Top 20 teams (WP_20).
Strength of Schedule (SOS):
The strength of schedule (SOS) is a broad measure of the quality of competition that a team competes against through the season. The SOS for each team is the sum of two factors: the average winning percentage of all the opponents of that team, multiplied by 2/3, and the average winning percentage of the opponents of each opponent of that team, multiplied by 1/3. This is a method used to calculate the strength of schedule that is widely used in many other sports. For a team whose opponents have a collective record of 23 wins and 17 losses, the winning percentage of the opponents (WP_OPP) would be 575. If for the same team, the opponents of their opponents have an overall record of 120 wins and 80 losses, the winning percentage of the opponent’s opponents (WP_OPP_OPP) would be 600. The resulting raw SOS would be 2/3 times the WP_OPP plus 1/3 times the WP_OPP_OPP or 583. In order to ensure that the SOS factor is balanced with the other two factors, the raw SOS for all teams is normalized so that the highest raw SOS within NESSA is scaled to 1000.
An interesting aspect of the SOS is that teams can be rewarded for competing against quality opponents even if they lose the meet. It is possible to gain 100-200 points in the SOS factor while losing only 50-100 points in the WP factor. Teams should also be cautious of creating schedules with a high potential SOS since it can also lead to a WP that is too low to be overcome – a lot of quality opponents with few wins to show for it.
Winning Percentage against Top 20 Teams (WP_20):
The winning percentage against Top 20 teams (WP_20) is a narrower measure of the quality of competition that a team competes against through the season, but it better reflects a team’s success against other teams that are likely to qualify for the NESSA Team Racing Championship. The WP_20 is the fraction of wins divided by the number of team racing meets against Top 20 teams. Which teams are included in the Top 20 is determined by calculating the Ratings Percentage Index (RPI) for all teams - the twenty teams with the highest RPI are in the Top 20. The RPI is a standard metric used in many sports and is generally defined as (WP/4) + (WP_OPP/2) + WP_OPP_OPP/4). Which teams are included in the Top 20 will change throughout the season with teams being added or dropped, based on their RPI, as the season progresses.
The Final Mark Ranking System:
Scores are reported to NESSA and posted on the NESSA website at http://www.taboracademy.net/nessa/all_results.asp. Standings by winning percentage, with links to results by individual teams, are posted at http://www.taboracademy.net/nessa/standings.asp. Using the posted scores, the computer ranking is done using a sophisticated MS Excel workbook with multiple worksheets. A hyperlink to a condensed version of this workbook is posted on same web page as the Standings.
A few weeks prior to the NESSA Team Racing Championship, a panel of coaches selected by the NESSA President ranks the teams that have applied for consideration to a berth in the NESSA Team Racing Championship. The average ranking of the coaches’ panel is then averaged with the computer ranking so that the computer ranking and human polling have equal weight. This combined ranking is used to determine which teams are invited to compete in the preliminary Wild Card Weekend sail-off and the Team Racing Championship.