Golfers improved by 10 strokes since 1934

This five-year-old golf study isn’t all that exciting, but it’s got useful information on how professional golfers have improved substantially over the last decades.

The study is called “Studying Improved Performance in Golf,” by Sangit Chatterjee, Frederick Wiseman, and Robert Perez. It looks at the winning scores from the Masters (72 holes), from 1934-2001, and finds:

-- the mean score improved from 296.5 to 286.3;
-- the median score improved at almost exactly the same rate;
-- the variance of scores dropped until the mid-80s, then levelled off;
-- the winning scores have been improving, but not as much as the mean;
-- but the extent to which the winner dominates the field has been fairly level.

The last two findings seem to contradict each other – if the mean is dropping, but the winning score isn’t dropping as much is the mean, doesn’t it follow that players are winning by less? I’m thinking it does follow. But the authors used Z-score (number of SDs above or below the mean) for their measure of domination -- since the variance of scores is also dropping, the Z-score is staying fairly level.