Comparison of Three Methods of Handling Missing Observations

With large-scale data collection stimulated by computer analysis the problem of what to do about missing observarions on Ss arises more often. In a research project by Turner, Guertin, and Cooper' correlations of GPA with 10 achievement rest scores were computed three ways because of missing scores for some Ss: ( a ) insert the mean score for that variable, ( b ) insert a multiple regression estimate, and ( c ) omit that S from the calculation. Results are given in the table, with the per cent of missing observations given in italics.