Friday, September 11, 2009

Why can IQ scores can differ: Applied Psychometrics 101 Report #1--Understanding global IQ test correlations

Announcing Applied Psychometrics 101: IQ Score Difference Series--#1 Understanding global IQ test correlations. (click here to view and/or download)

Toady I'm announcing the first in what I hope is a series of applied psychometric brief reports. The goal of this project is to explain basic psychometric issues to help professionals and the public better understand psychological measurement, IQ testing, etc. Above is the title of the first report (and a link where it can be accessed). Below is the abstract, followed by a few comments. This report (and future reports) are accessible via a section [(Applied Psychometric 101 (AP101) Reports] on the side bar of this blog.

Abstract
Despite reported evidence of strong concurrent correlations among IQ tests (concurrent validity), different IQ tests often produce different IQ scores for the same individual. This may be due to a number of factors. Prior to discussing the various factors, one must first understand the basic language of typical IQ-IQ comparison research. In the first of this series, IQ-IQ test correlations are explained. Statistically significant high correlations between different IQ tests, although providing strong concurrent validity evidence for tests, do not guarantee similar or identical IQ scores for all individuals tested.
Blogmaster comments

I've made a much longer series of comments regarding the questions and issues raised by this report as it relates to Atkins IQ MR death penalty cases at IQs Corner sister blog--Intellectual Competence and the Death Penalty. Visit it if you want more to think about.

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