An effect size primer: A guide for clinicians and researchers.

Abstract: Increasing emphasis has been placed on the use of effect size reporting in the analysis of social science data. Nonetheless, the use of effect size reporting remains inconsistent, and interpretation of effect size estimates continues to be confused. Researchers are presented with numerous effect sizes estimate options, not all of which are appropriate for every research question. Clinicians also may have little guidance in the interpretation of effect sizes relevant for clinical practice. The current article p… Show more

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“…As in Study 1, only these two variables exceed Ferguson's (2009) threshold (r=.2) for a practically significant association. Furthermore, the regression analysis (Table 6) indicates that it is only these two variables that are associated with Webexec scores.…”

“…Again, the very large sample size mandates consideration of effect size, and of whether relationships are sufficiently large to be important (as opposed to being statistically significant but trivial). Ferguson (2009) (2002) found that older adults scoring higher on Neuroticism were more likely to report mobility problems.…”

Self-report measures of executive function problems correlate with personality, not performance-based executive function measures, in nonclinical samples.

Researchers and clinicians often measure executive function in patients and normal samples. In addition to cognitive tests that objectively measure executive function, several instruments have been developed that address individuals' everyday experience of executive problems. Such selfreport measures of executive problems may have value, but there are questions about the extent to which they tap objectively-measurable executive problems or are influenced by variables such as personality. Relationships between self-reported executive problems, personality, and cognitive test performance were assessed in three separate, well-powered, methodologically distinct correlational studies using non-clinical samples. These studies used multiple measures of personality and self-reported executive function problems. Across all three studies, self-reported executive function problems were found to correlate with neuroticism and with low conscientiousness, with medium to large effect sizes. However self-reported problems did not correlate with performance on Trail Making, Phonemic Fluency, Semantic Fluency or Digit Span tests tapping executive function. A key implication of these findings is that in non-clinical samples, self-report questionnaires may not be proxies for executive functioning as measured by neuropsychological tests.

“…As in Study 1, only these two variables exceed Ferguson's (2009) threshold (r=.2) for a practically significant association. Furthermore, the regression analysis (Table 6) indicates that it is only these two variables that are associated with Webexec scores.…”

“…Again, the very large sample size mandates consideration of effect size, and of whether relationships are sufficiently large to be important (as opposed to being statistically significant but trivial). Ferguson (2009) (2002) found that older adults scoring higher on Neuroticism were more likely to report mobility problems.…”