How Accurate Are the STAR National Percentile Rank Scores for Individual Students?–An Interpretive Guide Version 1.0 August 1999 David Rogosa Stanford University
[email protected] 1. Introduction Parents and others use test scores from standardized testing programs like STAR to answer, at least in part, the basic question, How is my kid doing in school? For the Stanford 9 part of the STAR testing, the National Percentile Rank Scores are the main information provided in the 1999 STAR Parent Report. These percentile rank scores, which provide a comparison of the student's score to a national sample, are also featured in the 1998 Home Report and in the more extensive Student Report. For reference, below is an excerpt from a sample 1999 Grade 10 STAR Parent Report showing the percentile rank reporting for the Stanford 9. For readers unfamiliar with current California activities, basic information on the STAR testing program and the score reports is available from CDE: Reporting 1999 STAR Results to Parents/Guardians Assistance Packet. Percentile rank reporting from a sample 1999 Grade 10 STAR Parent Report. There is a public perception that these numbers are pretty solid. For example, last year in a discussion of the interpretation of individual scores: "Dan Edwards, the education spokesman for Gov. Pete Wilson, ...... said parents and policymakers should focus on a hard number, 'the national percentile rank, grade by grade'."Los Angeles Times, July 16, 1998 The whole idea of this interpretive guide is to apply some common-sense descriptions of accuracy to these National Percentile Rank Scores.