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CASAS Technical Manuals

The CASAS Technical Manuals are compiled to thoroughly document the research and development work done in the item and test development process. The manuals provide information about the purpose of each test series and the tests that are included in each series. Each technical manual provides information on a specific CASAS test series. The manuals are intended for state and local agency personnel as well as measurement specialists who are seeking specific technical information about the development and appropriate use of CASAS test instruments. Just as CASAS assessments are continually analyzed to insure that they remain reliable and valid, the technical manuals are continually updated with the latest research on the CASAS assessments. Although the development of CASAS assessment instruments from the multiple item banks are based on many traditional psychometric procedures including the preparation of test specifications, sound item writing practices, and both the pilot and field-testing of items using classical item analysis procedures, the underlying theoretical measurement foundation is IRT. The IRT model employed by CASAS for the development of the various item banks and the associated assessment instruments is the one parameter Rasch Model (1P-L).

The Development of CASAS tests is described which includes the item writing process, the pilot and field-test process, the process used calibrate and assign items to forms, and the results of the fairness and sensitivity reviews and psychometric analyses used to examine the performance of the test items and complete forms.

The Maintenance of CASAS tests is described which includes information about publishing dates for the CASAS assessments, steps taken to ensure score comparability across test forms, steps taken to maintain the security of the assessment, and a history of the assessments use.

Information on Content Validity, the degree to which the content of the test matches the entire content domain associated with the construct, includes the match of the content to the NRS Educational Functioning Levels, the content standards and competencies measured by the CASAS assessments, and the qualifications of the subject matter experts involved in the determination of content.

The Standard-Setting Procedures section describes the procedures used to establish cut scores for each NRS Educational Functioning Level and the standard error of measurement for each cut score.

Information on Reliability, the consistency of test scores or the degree to which CASAS assessments measure the same way each time they are used under the same condition with the same subjects, includes a description of the research designs used to test the reliability of the Life and Work Reading Assessments. Evidence of reliability included the correlation of scores across alternate or parallel test forms and classification consistency into NRS Educational Functioning Levels (EFL) when using alternate or parallel test forms.

Evidence of Construct Validity, the degree to which the assessment measures only the intended construct, includes information on the comparability of CASAS assessments with other assessments designed to assess educational gain for similar populations. Also included is additional evidence of convergent validity which shows the degree to which performance on CASAS assessments is correlated with other measures that it is theoretically predicted to correlate. Analyses regarding practice effects are also analyzed.

The Other Information section includes information on the determination of test administration time, appropriate modifications for individuals with a disability, and recommendations for retesting.

For more information on CASAS Technical Manuals please contact Jared Jacobsen jjacobsen@casas.org or Debalina Ganguli dganguli@casas.org.

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