Accuracy describes a measure’s ability to approach the true value of the quantity being measured. Any measure has the capacity for error due to variables and conditions. For example, a scale may not be very accurate if the spring it uses is old and not as flexible as it originally was. In language testing, a test has diagnostic accuracy if it is able to distinguish between typically developing and language impaired individuals with a high degree of accuracy (at least 80% of the time).
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Many clinicians label a child as language impaired (LI) or typically developing (TD) based on arbitrary cutoff scores (1.5 SD below the mean or 1 SD below the mean) on standardized tests. However, as demonstrated in this article, many standardized tests do not even provide information about validity and reliability.
Source URL: View this book on the Teacher’s College Press website
This book addresses the constellation of factors that have contributed to the misidentification of minority/culturally and linguistically diverse children as needing special education services. It also provides suggestions for improving the special education referral process.
Source URL: View this document on the ASHA website
Authors conducted a meta-analysis of diagnostic studies for language impairment in bilingual children. They found a serious lack of necessary psychometric measures in the vast majority of studies examined.
In this module, Cate discusses the validity of standardized tests and whether they measure what they claim to measure. Read More
In this module, Cate explains two types of reliability (test-retest and inter-examiner) in terms of standardized tests. Read More
This module further describes where clinical judgment comes from. Read More
In this module, Cate discusses the consequences of using test scores to determine disability. Read More
A standard deviation (SD) is a quantity derived from the distribution of scores from a normative sample. The standard deviation is the average distance (or deviation) from the mean. Read More
The LEADERSproject by Dr. Catherine (Cate) Crowley is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Based on a work at http://www.leadersproject.org.
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