Using a single question to assess physical activity in older adults: a reliability and validity study

Table 2 Convergent and discriminant validity results for PA questions

	Absolute Question^a	Relative Question^b
Validation Measure	r (95% CI)^c	r (95% CI)^c
Convergent validity
Total score on Berg Balance Scale (n = 158)	0.31 (0.17, 0.45)	0.48 (0.35, 0.59)
Unsteady gait (n = 152)	0.24 (0.12, 0.40)	0.40 (0.26, 0.56)
Gait-path (n = 93)	0.32 (0.17, 0.53)	0.57 (0.38, 0.78)
Gait-trunk (n = 94)	0.29 (0.15, 0.50)	0.42 (0.25, 0.63)
Gait-abnormality (n = 93)	0.26 (0.00, 0.47)	0.36 (0.20, 0.57)
Lower extremity weakness (n = 92)	0.21 (0.00, 0.43)	0.37 (0.21, 0.58)
Postural stability (n = 94)	0.17 (0.00, 0.38)	0.33 (0.17, 0.54)
Walking ability (n = 158)	0.33 (0.19, 0.49)	0.42 (0.28, 0.58)
Housework difficulty (n = 158)	0.28 (0.16, 0.45)	0.34 (0.20, 0.50)
Limits activity-fear of falling (n = 155)	0.10 (0.00, 0.26)	0.28 (0.15, 0.44)
Pain affects mobility (n = 90)	0.28 (0.00, 0.50)	0.34 (0.18, 0.55)
Discriminant validity
Home hazards (n = 152)	0.04 (0.00, 0.19)	0.02 (0.00, 0.12)
Vision (n = 157)	0.05 (0.00, 0.21)	0.07 (0.00, 0.23)
Skin problems (n = 157)	0.13 (0.00, 0.29)	0.15 (0.00, 0.32)
Hearing deficit (n = 94)	0.29 (0.15, 0.50)	0.24 (0.00, 0.44)

^a Response categories: i) seldom active; ii) moderately active; or iii) vigorously active.
^b Response categories: i) less active; ii) about as active; or iii) more active.
^c Specific type of correlation coefficient (r): Spearman's rho (total score on Berg Balance Scale) and Cramer's V (all other validation measures)
Validation measures and PA questions were ordered so that higher scores indicated better functioning or higher PA levels.
Abbreviations: CI = Confidence Interval; PA = Physical Activity.

ISSN: 1471-2288