Can round ratings be produced from your event format? ...or not?
PDGA members like getting their rounds rated whenever possible. But... sometimes an event format is different enough from standard singles disc golf that the rating process isn't designed to handle it properly or the format doesn't provide sufficient individual scores as with doubles and match play. Sometimes a format lends itself to separate ratings like we've done with Super Class events and could potentially do for minigolf if there were enough demand.
This story is about the challenges the ratings team has faced over the years trying to rate different types of events and the stats we review to make "Rate or Not to Rate" judgments. Players now take for granted that singles events can be rated regardless how long or short, open or wooded, hazards everywhere or penalty free, hilly or flat a course may be. We didn't know this was going to be true when the ratings process started but charged ahead to see what would happen. For each of these course elements, data has been analyzed over the years. We learned that ratings can be produced in singles play on courses with any mix of these elements.
However, there are still challenges at the extremes. For example, a course can be too short to provide proper ratings. It's not that ratings can't be mathematically determined. The problem is that a course can be so short that the scores may not differentiate very well between expert and average players. Experts can't shoot much better than 36 and average players can sometimes shoot close to 36. The lower limit for a course SSA that can provide ratings has been established at 41.4. Any lower than that and ratings become suspect. That's why the recommended minimum SSA for courses played in top tier events is at least 49 so players shooting well have scoring room to separate themselves from others.
TEE TIME ROUNDS
A different sort of challenge was provided when tee time rounds started to become popular. The ratings system was developed based on all players playing the same course at the same time with a shotgun start. The assumption was that all players would be affected in roughly the same way if weather changed during a round. With tee times, each playing group could have slightly to significantly different playing conditions depending when they started that round.
The ratings team has sometimes broken out the scoring information for tee time rounds and rated division groups separately if the separate SSA values showed enough difference from morning to afternoon rounds. However, large division groups can still be troublesome on occasion because scoring data from morning to evening can't easily be separated. In these cases, some players' ratings may benefit and some get penalized slightly depending whether their conditions were better or worse than the average conditions for the whole round.
The rating system is still evolving and is faced with some new challenges every so often. X-tier events usually have some format tweak making it inappropriate to calculate ratings. For example, a variety of mulligan formats do not get ratings on principle because a mulligan is not a game element allowed in the standard DG rules. Events sanctioned in winter or with night rounds have become more popular. Both winter and night rounds seem to provide appropriate ratings with the only difference that the SSA for a course may shift a little higher than when played in summer daylight.
The recent USDGC provided a trifecta of new challenges with its performance/handicap scoring, extensive throw & distance (T&D) penalties and the highest course SSA values ever recorded in competition. The statistical analysis of the scoring such as SSA variance, correlations and player standard deviations fell significantly outside the boundaries of any previous event so it was determined that no ratings could be provided. It's possible that future events incorporating just one of these three new elements - extensive T&D, performance scores/handicaps or extreme SSA >75 - might be rateable upon further analysis because the T&D format in the 2010 USDGC was rated. It was just the combination of all three new elements in one event which shifted the scoring pattern beyond the established boundary range for standard disc golf competition.
The ratings system has proven to be pretty flexible considering the variety of course configurations and formats it's been able to handle over the years. It can handle 13 to 30 hole courses over a 30-shot SSA range from 41 to 71 for 18 holes. It should be able to incorporate some new course elements and format elements as they evolve down the road from the fertile minds of our course designers and promoters.