The Vocabulary Test of the California Cognitive Assessment Battery (CCAB)

The CCAB vocabulary test adaptively administers 24 four-alternative synonym items in about 227 s and yields highly reliable QuickSIN scoring (retest r≈0.81–0.83).

• Why it matters: Existing vocabulary measures need well-calibrated item difficulty and dependable scoring across ages, plus clarity on which demographic factors relate to performance.
• What they did: In 2,181 English-speaking adults aged 18–89, the test used a 1-up/1-down staircase over 60 difficulty levels; Rasch dichotomous calibration calibrated stimulus difficulty and rescoring.
• The result: QuickSIN and last-four scores agreed closely (r=0.98), and Rasch rescoring increased 12-month retest reliability to 0.84; education, reading, and age correlated with performance.