Big Five validity: Aggregation method matters

Correlations between Big Five personality factors and other variables have been examined in three different ways: direct scoring of items within a factor, application of a composite score formula, and taking the average of single-scale correlations. Those methods were shown to yield consistently different outcomes in four sets of data from sales-people and managers. Factor correlations with job performance were greatest for direct scoring, and were reduced by half when scale correlations were averaged. The insertion of previously suggested estimates into the composite score formula yielded intermediate correlations with performance. It is necessary to interpret summary accounts of correlations with a compound construct in the light of the aggregation method employed.