Use of asynchronous e-learning modules was associated with an improvement in posttest scores ( p < 0.001 ) , from a mean score of 18.45 ( 95 % confidence interval [ CI ] = 17.92 to 18.98 ) to 21.30 ( 95 % CI = 20.69 to 21.91 ) , a large effect ( partial ( 2 ) = 0.19 ) .