Table 2

Condition-based mean values (M) and standard deviation (SD) for SF-12: mental (SF-12m) and physical (SF-12p) scales



Telephone interview
Self-administered questionnaire





Timing of information about second survey
Survey-mode sequence
SF-12p M (SD)
SF-12m M (SD)
SF-12p M (SD)
SF-12m M (SD)
N

Delayed
Self-administered questionnaire first
45.22 (10.0)
49.10 (10.6)
43.21 (10.0)
44.69 (11.3)
183

Telephone interview first
44.83 (11.0)
49.79 (9.8)
42.67 (10.6)
46.93 (10.5)
178

Total
45.03 (10.5)
49.44 (10.2)
42.94 (10.3)
45.79 (11.0)
361
At outset
Self-administered questionnaire first
43.91 (10.1)
48.19 (11.0)
42.32 (9.6)
44.35 (11.3)
183

Telephone interview first
43.68 (10.2)
49.80 (10.1)
42.35 (9.8)
47.01 (10.5)
164

Total
43.80 (10.2)
48.95 (10.6)
42.33 (9.7)
45.61 (11.0)
347
Total
Self-administered questionnaire first
44.57 (10.1)
48.65 (10.8)
42.77 (9.8)
44.52 (11.3)
366

Telephone interview first
44.28 (10.6)
49.80 (9.9)
42.51 (10.2)
46.97 (10.5)
342

Total
44.43 (10.3)
49.20 (10.4)
42.64 (10.0)
45.70 (11.0)
708

Lungenhausen et al. BMC Medical Research Methodology 2007 7:50   doi:10.1186/1471-2288-7-50