Table 1. Description of measures used in assessing performance of self-reported HIV status and self-reported ARV use (Nigeria HIV/AIDS and Indicator Survey 2018).

Performance measure (self-reported HIV status)	Description
Sensitivity	The proportion of participants who self-reported HIV-positive status among all those with confirmed final HIV positive test result.
Specificity	The proportion of participants who self-reported HIV-negative status among all those with confirmed final HIV negative test result.
Positive predictive value (PPV)	This is the probability that following a HIV positive self-report status, that participant will test positive for HIV after confirmatory HIV test.
Negative predictive value (NPV)	This is the probability that following a negative HIV self-report status, that participant will test negative for HIV after confirmatory HIV test.
Performance measure (self-reported ARV use)
Sensitivity	The proportion of participants who self-reported ARV use among all those who have detectable ARV in their blood specimens
Specificity	The proportion of participants who self-reported not using ARV among all those without detectable ARV in their blood specimens.
Positive predictive value (PPV)	This is the probability that following a self-report ARV use, that participant will have ARV detected in their blood specimen.
Negative predictive value (NPV)	This is the probability that following a self-report of not using ARV, that participant will not have ARV detected in their blood specimen.

Abbreviations: ARV, antiretrovirals.