Enhancing the effectiveness of contact tracing interviews: A randomized controlled experiment of an enhanced cognitive interview protocol.

Objectives: To compare the efficacy of a psychologically-based contact tracing interview protocol to a control protocol that emulated current practices under both interviewer-led and self-led modalities.

Methods: This randomized controlled experiment utilized a 2 × 2 factorial design (Enhanced Cognitive protocol vs Control protocol; Interviewer-led call vs Self-led online survey). Data were collected online (n = 200; M = 44; 56.5% female; 79.5% White) during the COVID-19 pandemic (July 2, 2020 - September 15, 2020).

Results: The Enhanced Cognitive protocol increased reported close contacts by 51% compared with the Control protocol (d = 0.44 [0.15, 0.71]). This effect was present for both interview modalities and for both identifiable and non-identifiable contacts. The Enhanced Cognitive protocol also increased both the quantity of person descriptors (d = 1.36 [0.87, 1.85]) and the utility of descriptions (r = 0.35 [0.13, 0.53]).

Conclusions: The application of cognitive principles in contact tracing interviews can significantly enhance the quantity and quality of information provided by respondents. Epidemiologists and public health investigators could benefit from utilizing cognitive principles and self-led modalities in contact tracing interviews.