The normative calculator is a tool for converting the patient’s raw scores on the Clock Drawing Test CDT), Shulman version to derived scores, i.e. percentiles, as a measure of how the patient performs compared to other people of the same age, gender and education level. The calculator covers the age range 25 – 95 years.
Instructions
Enter the patient’s age, gender, education level (in years), and attained CDT-score (0 – 5 points).
Gender
Education
Age
CDT
Percentile:
The percentile is the proportion of the population at same age, sex and educational level that has equal or lower score on the CDT.
Evaluation of test results
As a rule of thumb, a score between the 16th and 84th percentiles is usually considered within the normal/average range; a score between the 2nd and 15th percentile indicates below the average range; and a score below the 2nd percentile implies significantly below the average range («pathological range»). However, precaution in the interpretation of test scores is always required. Evaluation of a patient’s test scores should be done on an individual basis, and, among others, take into consideration the patient’s estimated premorbid cognitive functioning level and motivation in the test situation.