Table 2.

Agreement Between Encounter-Based Measures (R_EB) and Laboratory-Based Measures (R_LB) of Retention in Care for HIV-Positive Patients and Discrimination of R_EB by R_LB, NA-ACCORD, 2000–2010^a

Method of Parameter Estimation	No. of Observations	C Statistic	% Discordant	Sensitivity, %	Specificity, %	κ
Weighted data using IPW	468,816		17	86	79	0.63
Regression model with IPW	468,816	0.87	18	84	77	0.58

Abbreviations: HIV, human immunodeficiency virus; IPW, inverse-probability-of-selection weights; NA-ACCORD, North American AIDS Cohort Collaboration on Research and Design.

^a Estimated from a model using stabilized IPW constructed using clinic site, age, sex, race/ethnicity, and primary HIV risk factor.