The Biber Cognitive Estimation Test.

Normative data from 113 participants, and cross-validation data from 49 additional participants, are presented for the Biber Cognitive Estimation Test (BCET), a 20-item test with five estimation questions in each of four categories: time/duration, quantity, weight, and distance. In Study 1, the range of normal answers is provided for each item, and a cut-off for impaired performance is suggested. Although very low IQ or education levels would be expected to invalidate this test as a measure of estimation skills, participants in the current sample made few errors. In Study 2, a cross-validation suggested a slightly more conservative cut-off score for abnormality. Study 3 examined cognitive estimation in demented (dementia of the Alzheimer's type and dementia syndrome of Parkinson's disease) versus intact elderly participants. Results indicated that the BCET was able to distinguish between demented and intact elderly participants.