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In light of current concerns with replicability and reporting false-positive effects in psychology, we examine Type I errors and power associated with 2 distinct approaches for the assessment of mediation, namely the component approach (testing individual parameter estimates in the model) and the index approach (testing a single mediational index). We conduct simulations that examine both approaches and show that the most commonly used tests under the index approach risk inflated Type I errors compared with the joint-significance test inspired by the component approach. We argue that the tendency to report only a single mediational index is worrisome for this reason and also because it is often accompanied by a failure to critically examine the individual causal paths underlying the mediational model. We recommend testing individual components of the indirect effect to argue for the presence of an indirect effect and then using other recommended procedures to calculate the size of that effect. Beyond simple mediation, we show that our conclusions also apply in cases of within-participant mediation and moderated mediation. We also provide a new R-package that allows for an easy implementation of our recommendations. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The authors investigated how a collective self-construal orientation in combination with positive social comparisons "turns off" the negative effects of stereotype threat. Specifically, Experiment 1 demonstrated that stereotype threat led to increased accessibility of participants' collective self ("we"). Experiment 2 showed that this feeling of "we-ness" in the stereotype threat condition centered on the participants' stereotyped group membership and not on other important social groups (e.g., students). Experiment 3 indicated that in threat situations, when participants' collective self is accessible, positive social comparison information led to improved math test performance and less concern, whereas in nonthreat Situations, when the collective self is less accessible, positive comparison information led to worse test performance and more concern. Our final experiment revealed that under stereotype threat, only those comparison targets who are competent in the relevant domain (math), rather than in domains unrelated to math (athletics), enhanced participants' math test performance.

Procedures for examining whether treatment effects on an outcome are mediated and/or moderated have been well developed and are routinely applied. The mediation question focuses on the intervening mechanism that produces the treatment effect. The moderation question focuses on factors that affect the magnitude of the treatment effect. It is important to note that these two processes may be combined in informative ways, such that moderation is mediated or mediation is moderated. Although some prior literature has discussed these possibilities, their exact definitions and analytic procedures have not been completely articulated. The purpose of this article is to define precisely both mediated moderation and moderated mediation and provide analytic strategies for assessing each.