Thursday, January 03, 2008

WJ III NU (Normative Update) Assessment Service Bulletin #9 available

I'm pleased to announce that the Woodcock-Johnson III Assessment Service Bulletin 9: Woodcock-Johnson III®/Woodcock-Johnson III Normative Update Score Differences: What the User Can Expect and Why (click here to view/download) is now available. I want to thank all users for their patience during the delay in this publication. Below is the introduction to the document.

I want to thank Riverside Publishing for allowing me to post this publication today. In a few weeks it will be available for their web page. At that time I'll make a new post with the official link to the publication then being their web page.

[Conflict of interest disclosure - I'm a coauthor of the WJ III]

  • The Woodcock-Johnson III Normative Update (WJ III® NU) (Woodcock, McGrew, Schrank, & Mather, 2001, 2007) is a recalculation of the normative data for the Woodcock-Johnson III (WJ III) (Woodcock, McGrew, & Mather, 2001), based on the final 2000 U.S. census statistics (U.S. Census Bureau, 2005). The final 2000 census data are reflected in the norms provided by the WJ III Normative Update Compuscore® and Profiles Program (Compuscore) (Schrank & Woodcock, 2007) and in the documentation provided in the WJ III Normative Update Technical Manual (McGrew, Schrank, & Woodcock, 2007). The WJ III NU norms replace the original WJ III norms, which were based on the U.S. Census Bureau’s 2000 census projections issued in 1996 (Day, 1996).
  • The U.S. Census Bureau’s Population Projections Program issues projections of the United States resident population based on assumptions about future births, deaths, and international migration. Census projections are estimates of the population for future dates and are subsequently replaced by census statistics. The 2000 census statistics produced a somewhat different description of the U.S. population than was assumed from the last projections issued in 1996. For example, according to the bureau’s Greg Spencer, “When we took the 2000 census, we found about 6.8 million more people than we were expecting. When we went in and looked at the sources of that growth, we found that during the late 1990s, there was more migration than we had been measuring” (Landphair, 2004, p. 1). Other unanticipated changes in the population were documented (U.S. Census Bureau, 2005), including shifts in age, sex, race, Hispanic origin, and residence. Some states grew at three times the national rate, and people tended to cluster in locations where jobs were available and climate was preferred. For users of the WJ III, the normative update (WJ III NU) provides the most current comparisons to the U.S. population.
  • In addition, the WJ III NU used innovative statistical advancements to calculate the new norms. The use of bootstrap resampling procedures (Efron & Tibshirani, 1993) allowed for estimates of uncertainty and potential bias (in the sample data) to be incorporated into the calculation of the WJ III NU norms. The bootstrap-based norm development procedures used to recalculate WJ III NU norms result in more precise estimates of an individual’s tested performance. Collectively, the refinement of the demographic characteristics in the WJ III NU norm data, based on updated U.S. census statistics, and the use of state-of-the-art statistical methods for estimating the sample statistics used to calculate norms allow users of the WJ III to have greater confidence in the accuracy of the WJ III NU-based scores.

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