Table 3.

Results of interviews: correlation with external assessment of physical activity level

UCLA Activity scale
Absolute scores (total sample)
	Mean (SD)	Median [IQR]	Range
Patient	5.0 (1.7)	5 [4–6]	2–10
Surgeon	4.4 (1.6)	4 [3–6]	1–8
Physiotherapist	3.8 (1.3)	4 [3–4]	2–8
Differences (within-patient)
Patient minus	Mean (CI)	Median	Range
surgeon	0.6 (0.2–0.9)	0	–3 to 3
physiotherapist	1.2 (0.8–1.6)	1	–2 to 6
	Reliability	Agreement	Correlation
Patient minus	weighted Kappa	LoA	Spearman’s rho
surgeon	0.63	–2.0 to 3.1	0.65
physiotherapist	0.31	–2.0 to 4.4	0.47

Spearman’s rho correlation coefficient (–1 to 1) indicates the degree of linearity between measurement ranks. LoA = limits of agreement (mean ±2 SD). Differences are based on assessments within each patient.