Table 4. PROMIS anxiety short form item set: Reliability statistics (Cronbach's alpha, ordinal alpha, McDonald's Omega Total) and explained common variance (ECV) for the total sample and demographic subgroups (“Psych” R package).

	Cronbach's Alpha	Ordinal Alpha	McDonald's Omega	ECV
Total Sample	0.969	0.981	0.982	76.418
Random First Half Sample	0.969	0.982	0.982	76.568
Age 21 to 49 years	0.968	0.980	0.980	75.994
Age 50 to 64 years	0.971	0.982	0.982	77.419
Age 65 to 84 years	0.965	0.980	0.980	74.162
Male	0.968	0.982	0.982	75.931
Female	0.969	0.981	0.981	76.334
Non-Hispanic Whites	0.965	0.980	0.980	74.452
Non-Hispanic Blacks	0.970	0.983	0.983	77.218
Hispanics	0.968	0.980	0.980	76.177
Non-Hispanic Asians/Pacific Islanders	0.972	0.984	0.984	78.295
Less Than High School	0.969	0.980	0.980	76.207
High School Degree	0.969	0.981	0.981	76.311
Some College	0.970	0.982	0.983	76.958
College Graduate	0.963	0.980	0.980	73.581
Graduate Degree	0.956	0.977	0.977	70.207
Hispanics Interviewed in English	0.969	0.980	0.980	76.189
Hispanics Interviewed in Spanish	0.967	0.978	0.979	75.722