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. 2015 May 23;15:118. doi: 10.1186/s12888-015-0503-0

Table 3.

Item-level discrimination PHQ-9 (N = 676)

Item Item-test correlation Item-rest correlation Average Inter-item covariance Item Alpha
Phq1 0.578 0.429 0.144 0.734
Phq2 0.649 0.491 0.133 0.724
Phq3 0.619 0.440 0.135 0.734
Phq4 0.655 0.509 0.133 0.721
Phq5 0.620 0.451 0.135 0.732
Phq6 0.602 0.465 0.142 0.723
Phq7 0.587 0.466 0.147 0.730
Phq8 0.347 0.250 0.170 0.757
Phq9 0.546 0.420 0.150 0.736
Overall 0.143 0.756