where R 2 max is the upper-limit R 2 that can be obtained for a dataset with standard deviation of affinities (s (a f f inity)) and experimental uncertainty (s (measurement error)). The bCD dataset has a dynamic range of 1.99 kcal/mol (-4.47 to -6.46 kcal/mol), with s (a f f inity) of 0.545 and s (measurement error) of 0.015. Although the dynamic range is lower then the recommended 5-7 kcal/mol for a dataset , with a very low experimental uncertainty we can expect a R 2 max of 0.999. Similarly, with a WP6 experimental s (measurement error) of 0.012, a s (a f f inity) of 1.803, and a dynamic range of 5.44 kcal/mol (-5.40 to -10.84 kcal/mol) we can expect a R 2 max of 1.000. However, it would be reasonable to speculate that experimental uncertainties were underestimated, and if we guess a placeholder value of 0.5 as the s (measurementerror), the R 2 max would be 0.158 and 0.923 for the two datasets (bCD and WP6), respectively. Using this placeholder value for bCD dataset results in R 2 max value (0.158) that is lower than what some participants achieved (see Table ). Therefore, it is likely the true uncertainty is less than 0.5. A s (measurement error) value of 0.12 would yield R 2 max of 0.779, roughly matching the best R 2 a method achieved (0.78).