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. Author manuscript; available in PMC: 2012 Nov 1.
Published in final edited form as: Qual Life Res. 2011 Mar 16;20(9):1349–1357. doi: 10.1007/s11136-011-9882-y

Fig. 1.

Fig. 1

The test characteristic curve shows the most likely PHQ-9 sum score (on the y-axis) corresponding to an IRT-based PHQ-9 score (x-axis), which has been calibrated to the PROMIS metric. Horizontal lines indicate the published PHQ-9 cutpoints for mild (5–9), moderate (10–14), moderately severe (15–19) and severe (20–27) depression. Mild depression (PHQ-9 score of 5–9) corresponds to scores of 42–51 on the PROMIS metric, moderate depression to 52–63, moderately severe to 64–72, and severe to scores of 73 and higher