Table 2.

Minimally Important Difference (MID) for PROMIS Depression T-Score across Three Clinical Trials Using Different Methods^*

MID Estimation Method	Sample 1 (CAMEO) (N1=153)		Sample 2 (SPACE) (N2=240)		Sample 3 (SSSM) (N3=258)		Average Across Samples and Time
	Baseline	6 months	Baseline	3 months	Baseline	3 months
Distribution-based analysis
Effect size
• 0.2 standard deviation	2.04		1.89		1.97		1.97
• 0.35 standard deviation	3.57		3.31		3.45			3.44
• 0.5 standard deviation	5.09		4.73		4.93		4.92
Standard error of measurement
• 1-SEM	3.32		3.76		3.73			3.60
• 2-SEM	6.64		7.52		7.46		7.21
Cross-sectional anchors
Legacy measure cross-walk
• PHQ-9 change (3 points)	3.69	3.87	3.69	4.29	3.42	3.57		3.76
• PHQ-9 change (5 points)	6.15	6.45	6.15	7.15	5.70	5.95	6.26
Disability Days (past 4 weeks)
• 0–7 to 8–14	3.10	6.55	4.43	4.80	9.23	4.85	5.49
• 8–14 to 15–21	4.13	1.63	3.65	1.38	1.08	6.13	3.00
• 15–21 to 22–28	3.15	6.73	2.98	6.05	−0.35	−2.88	2.61
Average category shift change†	3.46	4.97	3.69	4.08	3.32	2.70		3.70
Longitudinal anchors
Prospective global change
• Same to Better		3.44		5.69		3.73	4.29
• Same to Worse		−1.70		−3.42		−3.12	−2.75
Average category shift change†		2.57		4.56		3.43		3.52
Retrospective global change
• Same to Better		2.74		2.29		0.30	1.78
• Same to Worse		−4.58		−3.84		−1.28	−3.23
Average category shift change†		3.66		3.07		0.79		2.51

^*The MID estimates in the table are the averages MID estimates across the 4 PROMIS scale versions. The 4 versions were comparable in MID estimates

^†Average category shift is the mean PROMIS T-score change between adjacent categories for these 3 categorical anchors