An illustration of using multiple imputation versus listwise deletion analyses: the effect of Hanen's "More than words" on parenting stress.

This investigation illustrates the effects of using different missing data analysis techniques to analyze effects of a parent-implemented treatment on stress in parents of toddlers with autism symptomatology. The analysis approaches yielded similar results when analyzing main effects of the intervention, but different findings for moderation effects. Using listwise deletion, the data supported an iatrogenic effect of Hanen's "More Than Words" on stress in parents with high levels of pretreatment depressive symptoms. Using multiple imputation, a significant moderated treatment effect with uninterpretable regions of significance did not support an iatrogenic effect of treatment on parenting stress. Results highlight the need for caution in interpreting analyses that do not involve validated methods of handling missing data.