Basal and Ceiling Scores on Normed Assessments

Giving normed measures to assess individuals for speech-language impairments may require demonstration of a basal score and a ceiling score to have reliable and valid testing scores. 

Basal:

 This is the point/item on a measure, where the GSC can feel confident that all items before this point/item will be correct.  Essentially, all the preceding items would be too easy for the client to complete.  Basal scores are established for each normed measure and the GSC can find what the basal will be in the testing manual and it is often noted on the test protocol.   For example:  Basal = 6 consecutive correct responses.  The GSC may started at item 10, which their client gets correct.  However, the client then misses item #11.  This means the GSC now must administered items #9,8,7 etc. until the client gets 6 consecutive correct answers.  The lowest point/item demonstrated to be successful is the basal score.  Then the GSC goes back to item #12 to continue testing.  When scoring the test, all items before the 6 consecutively correct items are assumed to be correct and are counted as correct. 

Ceiling

The is the point/item on a measure where the GSC can feel confident that the client has achieved the highest number of items correct.  Ceiling scores are established for each normed measure and the GSC can find this information in the testing manual and often on the testing protocol.  This is the termination point for testing.  For example:  Ceiling = 6 errors out of 8 responses.  The GSC must continue testing until the client scores 6 errors within 8 consecutive turns. Once this is achieved, the highest point/item is the ceiling score.  All items above this point/item are too difficult and will be in error. 

Happy, Reliable, Valid Assessments

PMD