A meta-analysis of job analysis reliability.

Average levels of interrater and intrarater reliability for job analysis data were investigated using meta-analysis. Forty-six studies and 299 estimates of reliability were cumulated. Data were categorized by specificity (generalized work activity or task data), source (incumbents, analysts, or technical experts), and descriptive scale (frequency, importance, difficulty, time-spent, and the Position Analysis Questionnaire). Task data initially produced higher estimates of interrater reliability than generalized work activity data and lower estimates of intrarater reliability. When estimates were corrected for scale length and number of raters by using the Spearman-Brown formula, task data had higher interrater and intrarater reliabilities. Incumbents displayed the lowest reliabilities. Scales of frequency and importance were the most reliable. Implications of these reliability levels for job analysis practice are discussed.