Exploring the aggregation of four functional measures in a population of older adults with joint pain and comorbidity

Table 2 Standardized factor loadings and reliability coefficients (omegas) of the most optimal model that combines (i) a bifactor model: general factor and 3 subgroup factors: physical functioning (PF; 10 items), ADL (A; 6 items), IADL (I; 7 items) and (ii) a separate but correlated factor participation (P; 6 items)

	Bifactor				Correlated factor	Residual variance
	General factor	Subgroup factors
	Functioning	PF	ADL	IADL	participation
PF1 Vigorous activities	0.723	0.046				0.475
PF2 Moderate activities	0.879	0.127				0.211
PF3 Carrying groceries	0.832	0.104				0.298
PF4 Climbing several stairs	0.845	0.346				0.167
PF5 Climbing one stair	0.830	0.384				0.163
PF6 Bending/kneeling	0.581	0.271				0.588
PF7 Walking > 1 kilometre	0.731	0.644				0.076
PF8 Walking 0.5 kilometre	0.625	0.747				0.050†
PF9 Walking 100 metres	0.623	0.755				0.043
PF10 Self-care	0.738	0.161				0.430
A1 Bathing	0.675		0.703			0.050†
A2 Dressing	0.621		0.710			0.110
A3 Toileting	0.608		0.525			0.355
A4 Continence	0.443		−0.016			0.803
A5 Getting out of chair	0.594		0.284			0.566
A6 Eating*	-		-			-
I1 Using telephone	0.384			0.896		0.050†
I2 Travelling	0.742			0.281		0.370
I3 Doing groceries	0.710			0.491		0.254
I4 Preparing meal	0.494			0.433		0.569
I5 Housework	0.747			0.230		0.389
I6 Taking medicine	0.673			0.197		0.508
I7 Managing money	0.397			0.443		0.646
P1 Mobility inside home					0.742	0.450
P2 Mobility outside home					0.876	0.232
P3 Self-care					0.743	0.448
P4 Looking after home					0.723	0.477
P5 Looking after belongings					0.766	0.414
P7 Interpersonal interactions					0.650	0.577
Correlations with the factor participation	0.507	0.229	0.261	0.283	1
Omega (total and subgroup)	0.94	0.94	0.50	0.72	0.82
Omega hierarchical	0.79
Omega-s		0.22	0.22	0.18
ECV	0.67

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