The Schmidt & Hunter (1998) meta-analysis is one of the most influential studies in industrial-organizational psychology. Analyzing 85 years of research on personnel selection, the authors evaluated how well different hiring methods predict job performance.
Their central finding is straightforward: general mental ability (GMA), often called cognitive ability, is one of the strongest predictors of job performance across occupations.
Across studies, Schmidt and Hunter found that cognitive ability predicts job performance with a correlation of approximately r = .51, substantially higher than traditional hiring signals such as education or years of experience.
The research also showed that combining cognitive ability with other structured selection methods significantly improves predictive accuracy. For example, pairing a cognitive ability assessment with a structured interview produces composite validity above .60, making it one of the most effective evidence-based hiring approaches.
The table below summarizes key validity findings reported in the Schmidt & Hunter meta-analysis.
Key Validity Findings from Schmidt & Hunter (1998)
| Selection method | Predictive Validity (r) | Notes |
|---|---|---|
| Work sample tests | 0.54 | Direct simulation of job tasks |
| General mental ability (cognitive ability) | 0.51 | Strongest general predictor across jobs |
| Structured interviews | 0.51 | Higher validity than unstructured interviews |
| Integrity tests | 0.41 | Often measures conscientiousness and reliability |
| Conscientiousness (personality) | 0.31 | One of the Big Five personality traits |
| Job experience (years) | 0.18 | Weak predictor of performance |
| Education level | 0.10 | Minimal predictive value |
Key takeaway: Traditional resume signals such as education and experience show relatively low predictive power, while cognitive ability and structured selection methods are far more reliable predictors of job performance.
What is Industrial/Organizational Psychology?
Industrial/Organizational (I/O) Psychology is the study of human behavior in the workplace. I/O Psychologists contribute to an organization’s success by improving performance, motivation, team effectiveness, job satisfaction, innovation, occupational health and well-being, and more. I/O Psychologists improve hiring, training, and management by studying worker behavior, evaluating companies, and conducting leadership training. I/O Psychology is one of the 15 recognized specialities in professional psychology in the United States.
Fortune 500 companies like Walmart, Amazon, and General Motors have in-house I/O Psychologists improving their employee selection, development, feedback, and more.
While the “organizational” side of I/O Psychology focuses on understanding how organizational structures and management styles affect individual behavior, the “industrial” side involves understanding how to best match individuals to specific jobs. A priority on this end of I/O Psychology is to gather evidence that identifies which selection methods best predict performance. Schmidt & Hunter’s research would fall into this category.
“The Validity and Utility of Selection Methods in Personnel Psychology,” explained
Frank L. Schmidt and John E. Hunter are American Industrial/Organizational Psychology PhDs, and in 1998 they published “The Validity and Utility of Selection Methods in Personnel Psychology.” What’s fascinating is that, although their research was published over 20 years ago, it remains one of the most influential publications on predictive talent selection methods to date (in fact, Schmidt, Oh, and Shaffer published an update to the 1998 publication in 2016 because of its influence in the I/O Psychology community). Even so, very few organizations have implemented their findings in their talent deployment processes.
Based upon their meta-analysis, Schmidt & Hunter argue three things:
- The best predictors of performance are cognitive ability, work sample tests, personality tests, and structured interviews
- Of these, cognitive ability is the #1 predictor of performance
- Selection methods drastically impact business outcomes
Let’s dig into each of these 3 takeaways.
1. The best predictors of performance are cognitive ability, work sample tests, personality tests, and structured interviews
Schmidt & Hunter summarize the practical and theoretical implications of 85 years of research in personnel selection, studying the validity of 19 selection procedures for predicting job performance. They found that cognitive ability, work sample tests, personality/integrity tests, and structured interviews are the best predictors of performance. We’ll focus specifically on personality and cognitive ability, because that’s exactly what Plum measures.
When it comes to personality assessment, Schmidt & Hunter note that their definition of integrity correlates with factors of the Big 5 personality model (which includes conscientiousness, extraversion, agreeableness, neuroticism, and openness to experience). You can read more about the Big 5 model and how it relates to job performance here.
In terms of basic personality tests, integrity tests have been found to measure mostly conscientiousness, but also some components of agreeableness and emotional stability (Ones, 1993).
Although personality was a predictive indicator of performance, Schmidt & Hunter found that cognitive ability was the absolute best predictor of whether or not someone would succeed in a role.
2. Cognitive ability is one of the strongest predictors of job performance
Schmidt & Hunter found that General Mental Ability (GMA) has a strong correlation with job performance, especially when compared with traditional resume signals. In behavioral science, correlations are measured using coefficients (r). These coefficients range from -1.0 to +1.0, and when it comes to selection tests, a coefficient of 0.35 and above is considered highly useful.
Schmidt & Hunter found that experience and education (what you would typically find on a resume) have correlations of 0.18 and 0.10 with job performance respectively, coefficients that are defined as “unlikely to be useful.” General Mental Ability, on the other hand, has a correlation coefficient of r = 0.51, meaning it is strongly predictive of on-the-job performance.
3. Selection methods drastically impact business outcomes
Schmidt & Hunter’s article also touches on the ROI of selection methods, and that the difference between success and failure in a business is based upon their selection methods. Schmidt & Hunter lay down some very quotable truth:
In fact, many employers are currently using suboptimal selection methods. For example, many organizations hire new employees based on handwriting analyses by graphologists. And many organizations rely solely on unstructured interviews when they could use more valid methods.
Conclusion
Schmidt & Hunter conclude their publication stating that employers must make hiring decisions, but they can choose which methods to use in making those decisions.
When it came to combining predictors of success, several combinations stood out. The combination of a GMA test and an integrity test had a composite validity of 0.65. The combination of a GMA test and a work sample test had a composite validity of 0.63. The combination of a GMA test and a structured interview also had a composite validity of 0.63.
It’s because of Schmidt & Hunter’s research that we measure personality and two subcategories of GMA (fluid intelligence and social intelligence) here at Plum.
To learn more about how Plum brings valid and predictive selection methods backed by 50+ years of Industrial/Organizational Psychology research to organizations, book a demo with us.