Selection science — Schmidt & Hunter's 100-year meta-analysis, updated
The single most cited paper in I/O psychology — Schmidt & Hunter's 1998 meta-analysis ranked every predictor of job performance.
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- Top predictors (validity coefficients): structured interviews (~0.58), work sample tests (~0.54), GMA tests (~0.51-0.65), integrity tests (~0.46).
- Bottom predictors: graphology, years of education, age, interest inventories — near zero.
- Unstructured interviews are weak (~0.20) yet ubiquitous. Structure is the single biggest legal + scientific win you can make this quarter.
- Combine 2-3 predictors with low overlap (e.g. work sample + structured interview + integrity) for compounding validity.
Hiring is the single most consequential HR decision. The science is unusually clear — and unusually ignored. Schmidt & Hunter ran the meta-analysis; Sackett et al. updated it in 2022. Use it.
What the meta-analysis says
| Predictor | Validity (r) | Notes |
|---|---|---|
| Structured interview | 0.58 | Standardised questions, scored against a rubric |
| Work sample test | 0.54 | Realistic task from the job itself |
| GMA (cognitive ability) | 0.51–0.65 | Often legally constrained in some jurisdictions |
| Integrity test | 0.46 | Predicts counterproductive work behaviour |
| Job knowledge test | 0.48 | Strong for technical roles |
| Unstructured interview | 0.20 | Ubiquitous, weak, and bias-prone |
| Years of experience | 0.18 | Surprisingly weak above 1-2 yrs |
| Graphology | 0.02 | No predictive value |
What changed in the update
Sackett, Zhang, Berry & Lievens (2022) re-estimated the validities after correcting for over-corrections in the original meta-analysis. GMA dropped from ~0.65 to ~0.31-0.42; structured interviews held up; work samples remained strong. The hierarchy mostly stands; the absolute numbers are more modest.
Building an evidence-backed process
- Define the job competencies (≤6).
- Pick 2-3 predictors that map to them and have low overlap.
- Score every candidate on the same rubric.
- Use compensatory or multiple-hurdle scoring — decide in advance.
- Audit hires + performance after 6 and 18 months. Recalibrate.
Validity science is necessary but not sufficient. Adverse impact testing (4/5ths rule in US) must run alongside. A predictor that works but discriminates is still illegal.
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