Combined effects, total unique effects and relative weights of perfectionism

It has recently been argued that because the major two dimensions of perfectionism (perfectionistic strivings and perfectionistic concerns, PS and PC) can have opposing effects, the “combined effect” should be calculated to understand whether, overall, perfectionism is neutral, adaptive, or maladaptive. In this methodological note we revisit the task of disentangling the overall effects of PS and PC. In doing so, we illustrate a new and alternative approach – calculation of the total unique effect and the relative weights of PS and PC. The total unique effect is the simplest way of ascertaining whether perfectionism is neutral, adaptive, or maladaptive. However, like the combined effect, it does not convey information regarding the relative importance of PS and PC. Calculating the relative weights of PS and PC does so and provides a fuller account of the overall effect of perfectionism and the precise role of each dimension when predicting a given outcome. We close the paper by applying this approach to a range of outcomes reported in recent meta-analyses in this area. In doing so, perfectionism is revealed to be primarily maladaptive and rarely adaptive or neutral, with the relative contribution of perfectionistic concerns being the main reason why this is the case. •Perfectionism includes dimensions that can have opposing effects.•A new approach to determining the overall effect of perfectionism is illustrated.•Perfectionism is revealed to be primarily maladaptive and rarely adaptive or neutral.