As a simple test of independence, I calculated correlations between the normalized RCFR, RRF9R, DP/E, and DPdg.
Perhaps most importantly, the intuitive notion that sure-handedness (proxied by RCFR) and range (proxied by RRF9R) are largely independent, complementary measures of fielding is supported by this statistical analysis.
These correlations also confirm that DP/E reinforces the measure of sure-handedness, but it is not a carbon copy of RCFR and exhibits virtually no relationship with range.
In summary, this statistical analysis provides some encouragement for including all four measures in the calculations and rankings that follow, giving priority to RCFR and RRF9R as the dominant measures of fielding.
Range-Biased Score = 60% RCFR + 30% RRF9R + 5% DP/E + 5% DPd9
Sure-Handedness (SH)-Biased Score = 60% RRF9R + 30% RCFR + 5% DP/E + 5% DPd9,