Comparison of enrichment estimation methods by MARS model statistics. Plots of (A) GCV and (B) R-squared values for MARS models built with each enrichment estimation method. GCV scores are sorted in descending order; small GCV scores are indicative of superior model fit. R-squared values are sorted in ascending order; large R-squared values are indicative of superior model fit. Models based on whole-gene enrichment estimates group together as the best models by both metrics.