 By retaining E, P, and Z as separate variables, results from polynomial regression equations can be translated into three-dimensional surfaces, whose properties can be formally tested using procedures set forth by Edwards and Parry (1993; see also Edwards, 2002).Studies using polynomial regression have found that the restrictive assumptions underlying difference scores are usually rejected, such that the relationship of the person and environment to outcomes is more complex than the simplified functions represented by difference scores.These findings have provided a foundation for developing fit hypotheses that are more refined than those considered in prior research, such as considering whether the effects of misfit are asymmetric and whether outcomes depend on the absolute levels of the person and environment (e.g., the effects of fit between actual and desired job complexity are likely to vary depending on whether job complexity is low or high; Edwards & Shipp, 2007).