Researchers' choice of the number and range of levels in experiments affects the resultant variance-accounted-for effect size.
Psychon Bull Rev
; 24(2): 607-616, 2017 04.
Article
en En
| MEDLINE
| ID: mdl-27503194
ABSTRACT
In psychology, the reporting of variance-accounted-for effect size indices has been recommended and widely accepted through the movement away from null hypothesis significance testing. However, most researchers have paid insufficient attention to the fact that effect sizes depend on the choice of the number of levels and their ranges in experiments. Moreover, the functional form of how and how much this choice affects the resultant effect size has not thus far been studied. We show that the relationship between the population effect size and number and range of levels is given as an explicit function under reasonable assumptions. Counterintuitively, it is found that researchers may affect the resultant effect size to be either double or half simply by suitably choosing the number of levels and their ranges. Through a simulation study, we confirm that this relation also applies to sample effect size indices in much the same way. Therefore, the variance-accounted-for effect size would be substantially affected by the basic research design such as the number of levels. Simple cross-study comparisons and a meta-analysis of variance-accounted-for effect sizes would generally be irrational unless differences in research designs are explicitly considered.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Psicología Experimental
/
Proyectos de Investigación
/
Interpretación Estadística de Datos
Límite:
Humans
Idioma:
En
Revista:
Psychon Bull Rev
Asunto de la revista:
PSICOLOGIA
Año:
2017
Tipo del documento:
Article