Tracked the effect of candidate response patterns on a computerized adaptive test. Data were from a certification examination in laboratory science administered in 1992 to 155 candidates, using a computerized adaptive algorithm. The 90-item certification examination was divided into 9 units of 10 items each to track the pattern of initial responses and response alterations on ability estimates and test precision across the 9 test units. The precision of the test was affected most by response alterations during early segments of the test. While candidates generally benefited from altering responses, individual candidates showed different patterns of response alterations across test segments. Test precision was minimally affected, suggesting that the tailoring of computerized adaptive testing is minimally affected by response alterations. (PsycINFO Database Record (c) 2002 APA, all rights reserved).