Healy and Westmacott (1956) gave an iterative missing value procedure in which a simple correction is subtracted from each estimated missing value at each iteration. Experience has however shown that it is advantageous to replace the simple correction by a multiplemof it,m> 1. The multiplierm=n/E, wherenis the number of units andEthe number of error degrees of freedom in the absence of missing values, gives an exact solution in one step for most factorial analyses with one missing value; for other analyses, also, convergence is faster withm=n/Ethan withm= 1.