by Valerie Johnston, MS, CCC-SLP
Assessment can be defined in many different ways and accomplished through the use of many different techniques and procedures. However, all assessments have one characteristic in common: their purpose, which is to assist professionals in making decisions about a person's abilities and needs in a given area.
Speech-language pathologists assess individuals to determine if a communication disorder exists, to identify specific areas of strength and weakness, to set goals for intervention and to measure progress. In order to accomplish these purposes, formal norm-referenced and criterion-referenced tests and informal measures are utilized.
Norm-referenced tests are tools that provide norms, or statistics, by which meaning can be given to obtained test scores. The most commonly used norms are intelligence quotients (IQ's), standard scores, and percentiles. Some norm-referenced tests also allow for comparison of an individual's abilities in several areas, which helps identify specific areas of strength and weakness.
The norms for these tests are based upon the actual performance of individuals in the standardization sample, which is typically divided into categories, such as race, gender, age, grade, etc. In order to use the norms, the raw score an individual earns on the test is compared to the subgroup of the standardization sample that most closely matches his age or grade. Since norm-referenced tests compare the individual's performance with that of his peers (the standardization sample), it is tests from this category that are most frequently used to identify the presence of communication disorders.
Criterion-referenced tests compare a person's performance to a predetermined sequence of skills or abilities rather than to the performance of a peer group. This type of test measures development of certain skills in terms of absolute levels of mastery. Test items are typically arranged in hierarchical order and scores are reported as ratios of performance at a given level. Tests from this group are used primarily to set goals for intervention and less frequently to identify disorders and areas of strength and weakness.
Informal tests are designed by their users to obtain more detailed information about an individual's performance in a specific area, such as the use of question forms. They usually focus on areas of weakness that were identified during formal testing or by observations of the individual's speech and language made by the speech-language pathologist. The specificity of the information provided by informal testing, along with information obtained from criterion-referenced testing, enables speech-language pathologists to set appropriate goals for intervention. In addition, informal tests can be used to obtain pre- and post-intervention levels, which are needed to measure progress during the course of treatment.
Each of the above categories of tests has its place in assessment. It is through the appropriate selection and use of a combination of norm-referenced, criterion-referenced and informal tests that professionals are able to successfully identify disorders and areas of strength and weakness, set goals for intervention and measure progress.
If you have questions or need more information you can contact us at:
Speech & Language Center, Inc.
4763 Barwick Drive, Suite 103
Fort Worth, TX 76132