Retest reliability of the woodcock language proficiency battery

The Woodcock Language Proficiency Battery: English Form was administered to 152 of the 478 students beginning medical studies at an Australian university in 1990 and 1991. Two years after admission 147 of the students were available for retest. Test-retest reliability coefficients ranged from .70 to .85 for the 8 subtests, .83 to .91 for the three cluster scores, and the coefficient for the Broad Language Cluster score was .95. The sample had deliberately over-represented students low in English language proficiency but the reliability coefficients were only slightly reduced when this bias was corrected by forming a representative sample of 72 students. The mean incremental gain on the Broad Language Cluster of 1.8 was statistically significant and corresponded closely to the 2.0 predicted from the test norms for a 2-year developmental period. These results support previous reports of the excellent psychometric properties of this instrument.