Measurement invariance across chronic conditions: a systematic review and an empirical investigation of the Health Education Impact Questionnaire (heiQ™)

Table 3 Results of tests of MI across five chronic conditions, arranged by type of parameter

Scale	Configural MI	Metric MI			Scalar MI			Strict MI
		Diag	Item	EPC	Diag	Item	EPC	Diag	Item	EPC
Positive and active engagement in life	✓		✓		ortho	2	-0.24	copd	2	0.13
					ortho	5	-0.18
					asthma	2	-0.17
					asthma	10	0.12
Health-directed activities	✓		✓		copd	19	0.24		(✓)
Skill and technique acquisition	✓		✓		copd	23^a	-0.17	ortho	30	0.19
Skill and technique acquisition	✓		✓		asthma	23^a	-0.09	ortho	30	0.19
Constructive attitudes and approaches	✓	copd	36	0.16	rheuma	36	0.13		(✓)
Self-monitoring and insight	✓	ortho	11^a	-0.14	ortho	3	-0.10	ortho^b	11	-0.13
					ortho	17	-0.13
					asthma	3^a	-0.22
					asthma	17^a	-0.20
					copd	3^a	-0.31
		cancer	11^a	-0.15	copd	6	0.34
					copd	17^a	-0.21
					cancer	6	-0.28
Health-service navigation	✓		✓		ortho	33^a	-0.21		(✓)
Health-service navigation	✓		✓		rheuma	33^a	-0.29		(✓)
Social integration and support	✓		✓			✓			✓
Emotional distress	✓		✓		cancer	12	-0.19	ortho	7	-0.16

Notes: MI: measurement invariance; numbers (“Item”) represent non-invariant heiQ™ items in the mentioned disease group (“Diag”), followed by EPC (Expected Parameter Change) with ortho = orthopedic conditions, rheuma = rheumatism; ✓: all parameter invariant; (✓): no new DIF parameter, but parameters of items with DIF in a former stage were set free; ^ainvariant parameter in subgroups (for example item 3 has the same intercept in COPD and asthma); ^bin item 11, orthopedic group and cancer group show same factor loadings and intercept, but differ in residual variances.

ISSN: 1477-7525