The Thurstone Word Fluency Test, also known as the Chicago Word Fluency Test (CWFT),[1] was developed by Louis Thurstone in 1938.
[3] The test is a used to measure an individual's symbolic verbal fluency.
[4][5][6] The test asks the subject to write as many words as possible beginning with the letter 'S' within a 5-minute limit, then as many words as possible beginning with letter 'C' within 4 minute limit.
The total number of 'S' and 'C' words produced, minus the number of rule-breaking and perseverative responses, yield the patients' measure of verbal fluency.
The CWFT is used as one of the measures of brain's frontal lobe function.