W scores are used in a number of commercially available tests. Due to their complex nature, it can be hard for applied researchers and practitioners to understand them or even acquire information about them beyond what is provided in technical manuals. In this article, we provide information regarding the background and derivation of W scores that can aid in understanding and appropriate utilization of these scores.
BondT. G.FoxC. M. (2007). Applying the Rasch model: Fundamental measurement in the human sciences (2nd ed.). Mahwah, NJ: Lawrence Erlbaum.
2.
JaffeL. E. (2009). Development, interpretation, and application of the W score and the relative proficiency index (Woodcock-Johnson III Assessment Service Bulletin No. 11). Rolling Meadows, IL: Riverside.
SchrankF. A.MatherN.McGrewK. S. (2014). Woodcock-Johnson IV Tests of Achievement. Rolling Meadows, IL: Riverside.
5.
SchrankF. A.McGrewK. S.MatherN. (2014). Woodcock-Johnson IV Tests of Cognitive Abilities. Rolling Meadows, IL: Riverside.
6.
WoodcockR. W. (1999). What can Rasch-based scores convey about a person’s test performance? In EmbretsonS. E.HershbergerS. L.EmbretsonS. E.HershbergerS. L. (Eds.), The new rules of measurement: What every psychologist and educator should know (pp. 105-127). Mahwah, NJ: Lawrence Erlbaum.
7.
WoodcockR. W.DahlM. N. (1971). A common scale for the measurement of person ability and item difficulty (AGS Paper No. 10). Circle Pines, MN: American Guidance Service.
8.
WrightB. D.MokM. M. C. (2004). An overview of the family of Rasch measurement models. In SmithE. V.SmithR. M. (Eds.), Introduction to Rasch measurement: Theory, models and applications (pp. 1-24). Maple Grove, MN: JAM Press.
9.
WrightB. D.PanchapakesanN. (1969). A procedure for sample-free item analysis. Educational and Psychological Measurement, 29, 23-48. doi:10.1177/001316446902900102