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Criticisms of Meta-Analysis. Algera et al. Definition of rho Predictor Criterion Population Model is for a single combination in a single population. Applied to multiple predictors, criteria, unspecified population(s). JAP, a meta-analysis. Criterion Measures.
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Algera et al. • Definition of rho • Predictor • Criterion • Population • Model is for a single combination in a single population. Applied to multiple predictors, criteria, unspecified population(s). • JAP, a meta-analysis
Criterion Measures • Homogeneity of predictors and criteria • Supervisory ratings mostly • Multidimensionality of criteria
75 percent rule Unknown type I and type II error rates. Depends heavily on N/study Assumption that 25 percent is due to junk Q (chi-square) test Power depends on k Not worked out for corrected effect sizes Test of Situational Specificity
SS vs. VG • Situational Specificity rejected if V(rho)=0. • Validity Generalizes if V(rho) >0 and CRLow > some value. • What test (predictor)? • What criterion? • What population?
Meanings of Situation • Outside the individual e.g., working conditions, pay for performance • Nature of job performance, dimensionality, criterion factor structure (considered SS by SnH) • Research design, e.g., time between measurements, reliability, range restriction, etc.
REVC is unsatisfactory • REVC represents unexplained variability in effect sizes • Theory is all about explanation • A good theory of, e.g., Situation, will result (ultimately) in a single estimate of rho.
Sharpe • Apples & Oranges • File Drawer • GIGO, study rigor
Apples & Oranges • Inclusion criteria • Homogeneity test • Not really helpful • The problem of moderators • May be sig moderator even if overall Q is n.s. • Quickly exhaust studies with multiple moderators
File Drawer • Explain search for studies • Include published & unpublished studies, depending on study purpose • Report correlation between sample size and effect size • Calculate fail-safe N • May not be very meaninful, tho, assume ES=0, but ES could be negative • Use sophisticated bias detection methods, e.g., trim & fill
GIGO • Are published studies really better? • “Best-evidence” synthesis • Meta-analyze only the best studies • Major disagreements about what ‘best’ means • Code for features, e.g., random assignment, blind to condition
Borenstein et al. issues • One number cannot summarize a field • File drawer problem • Mixing apples and organes • Garbage in, garbage out • Important studies are ignored • Meta-analysis can disagree with randomized trials • Meta-analyses are performed poorly
Other issues • Conclusions of meta-analyses disagree • Premature closure of research areas