Title
Adjustments for rater effects in performance assessment
Abstract
Alternative methods to correct for rater
leniency/stringency effects (i.e., rater bias) in performance
ratings were investigated. Rater bias
effects are of concern when candidates are
evaluated by different raters. The three correction
methods evaluated were ordinary least squares
(OLS), weighted least squares (WLS), and
imputation of the missing data (IMPUTE). In
addition, the usual procedure of averaging the
observed ratings was investigated. Data were
simulated from an essentially τ-equivalent measurement
model, with true scores and error scores normally
distributed. The variables manipulated in the
simulations were method of correction (OLS, WLS,
IMPUTE, averaging the observed ratings), amount
of missing data (50% missing, 75% missing), rater
bias (low, high), and number of examinees or candidates
(N = 50, N = 100). The accuracy of the
methods in estimating true scores was assessed
based on the square root of the average squared
difference between the estimated and known true
scores. The three correction methods consistently
outperformed the procedure of averaging the
observed ratings. IMPUTE was superior to the least
squares methods. Index terms: EM algorithm,
incomplete data, incomplete rating designs, least
squares adjustments, performance assessment, rater
calibration.
Identifiers
other: doi:10.1177/014662169101500411
Previously Published Citation
Houston, Walter M, Raymond, Mark R & Svec, Joseph C. (1991). Adjustments for rater effects in performance assessment. Applied Psychological Measurement, 15, 409-421. doi:10.1177/014662169101500411
Suggested Citation
Houston, Walter M.; Raymond, Mark R.; Svec, Joseph C..
(1991).
Adjustments for rater effects in performance assessment.
Retrieved from the University of Minnesota Digital Conservancy,
https://hdl.handle.net/11299/114470.