Table 3.

Classification of Clinical Diagnosis and Demographic Groups for Invariance Testing

Variable	Group	n
Diagnosis	Cognitively unimpaired	317
	Dementia / MCI a	82
Sex	Male	171
	Female	240
Race / Ethnicity	Under represented groups (URG)	90
	Non-URG	314
Age	< 65 years	165
	≥ 65 years	152
Education	Without bachelor’s degree (low)	144
	With bachelor’s degree (high)	267

Note. Because of the limited sample size in each impaired group, dementia and MCI due to all causes were combined into one group, whereas the impaired not MCI were excluded from the invariance testing. Due to a similar consideration, race/ethnicity groups were classified as underrepresented groups (URG) versus non-URG. Following the NIH definition (NIH Diversity in Extramural Programs, 2019), a participant was classified as URG if s/he self-reported primary, secondary, or tertiary race as African American, American Indian or Alaska native, Native Hawaiian or other Pacific Islander, or self-reported Hispanic ethnicity. A participant was classified as non-URG if s/he self-reported only White or Asian in primary and secondary races and self-reported No to Hispanic ethnicity. A participant was classified as URG unknown and not included for the invariance testing, if s/he self-reported other or unknown in race or ethnicity. Age was classified as a binary variable, < 65 versus ≥ 65, since around 65 is commonly considered as the start of late adulthood. Because age is the biggest risk factor for dementia/MCI, and in the current sample age was highly associated with the incidence rate of dementia/MCI, 6.8% for participants < 65 versus 31.5% for those ≥ 65, p < .0001 (Fisher’s exact test), age invariance was tested only for cognitively unimpaired participants. Education level was classified into low (without bachelor’s degree) versus high (with bachelor’s degree) education groups, as these two groups would likely have access to different occupations, involving different cognitive demands and leading to different social economic status.

^a72 out of the 82 dementia / MCI participants had AD as a cause.