TABLE 1.

Strengths and Limitations of Commonly Used DIS Performance Metrics for STD and HIV Investigations

Commonly Used Metric	Definition	Strengths	Limitations
Contact Index	No. contacts/no. case patients*	• Measure important steps of a DIS investigation • Straightforward • Easy to calculate • DIS routinely collect these data during investigations • Input data are readily available in program databases • Based on longstanding disposition codes widely used by DIS	• Does not consider unnamed contacts • Does not consider unreported contacts • Does not capture the number of people notified or treated due to the indirect work of DIS • Misclassification of disposition codes used to inform performance metrics is possible • Diagnosis and treatment of comorbid conditions not always (well) captured or reported • Referrals to other public health services not always (well) captured or reported
Notification Index	No. contacts notified/no. case patients*
Case-finding Index	No. contacts found to be infected/no. case-patients*
Treatment Index	No. contacts treated/no. case-patients*
Brought-to-Treatment Index	No. infected contacts who were treated because of DIS efforts/no. case-patients*

*Denominator can be all reported, assigned, or interviewed case patient.