A primer on method effects on observed correlations with examples

I use a path/confirmatory factor analytic framework to present an under-the-hood introduction to (a) the effects of measurement error and method variance on observed measures, (b) the effects of common latent Trait and Method factors on relationships between observed measures in the presence of measurement error and (c) examine implications of developments presented here for the possible reinterpretation of Campbell and Fiske's original criteria for convergent and discrimainat validity and presence of common method bias. I use results from one previously published and often-cited primary study and four meta-analyses of multitrait–multimethod studies to provide empirical examples to illustrate points made here. I show analytically that (a) some common interpretations of method effects are correct, (b) others are incorrect and (c) still others are more nuanced than is usually recognised. Finally, I offer some suggested directions for future research.