Buy three but get only two: The smallest effect in a 2 × 2 ANOVA is always uninterpretable


Autoria(s): Garcia-Marques, Leonel; Garcia-Marques, Teresa; Brauer, Markus
Data(s)

29/12/2016

29/12/2016

2014

Resumo

Loftus (Memory & Cognition 6:312-319, 1978) distinguished between interpretable and uninterpretable interactions. Uninterpretable interactions are ambiguous, because they may be due to two additive main effects (no interaction) and a nonlinear relationship between the (latent) outcome variable and its indicator. Interpretable interactions can only be due to the presence of a true interactive effect in the outcome variable, regardless of the relationship that it establishes with its indicator. In the present article, we first show that same problem can arise when an unmeasured mediator has a nonlinear effect on the measured outcome variable. Then we integrate Loftus's arguments with a seemingly contradictory approach to interactions suggested by Rosnow and Rosenthal (Psychological Bulletin 105:143-146, 1989). We show that entire data patterns, not just interaction effects alone, produce interpretable or noninterpretable interactions. Next, we show that the same problem of interpretability can apply to main effects. Lastly, we give concrete advice on what researchers can do to generate data patterns that provide unambiguous evidence for hypothesized interactions.

Fundação para a Ciência e a Tecnologia (FCT)

info:eu-repo/semantics/publishedVersion

Identificador

Psychonomic Bulletin and Review, 21, 1415-1430. Doi: 10.3758/s13423-014-0640-3

1069-9384

http://hdl.handle.net/10400.12/5181

10.3758/s13423-014-0640-3

Idioma(s)

eng

Publicador

Springer Verlag

Relação

info:eu-repo/grantAgreement/FCT/3599-PPCDT/111992/PT

http://link.springer.com/article/10.3758%2Fs13423-014-0640-3

Direitos

restrictedAccess

http://creativecommons.org/licenses/by-nc-nd/4.0/

Palavras-Chave #Statistics #Statistical inference
Tipo

article