Figure 2
From: Development of computer adaptive testing for measuring depression in patients with cancer
Lowess curves for the standard error of measurement (SEM) by θ (degree of depression). Each line indicates the Lowess curve for SEMs in each estimation (□, estimation using the calibrated PHQ-9; ○, 4-item CAT; △, 8-item CAT). The measurement precision of CAT using only four items surpassed that of the estimation using the calibrated PHQ-9.
