Table 2.

Behavioral determinants influencing adoption of three core behaviors of household TB contact investigation, and possible intervention functions specified by the behavior change wheel framework.

COM-B determinants of behavior	Is change needed for the key behaviors to occur?
	Agree to contact investigation (Index cases)	Screen contacts for TB (Lay health workers)	Complete TB evaluation (Contacts)
Physical capability	No, index patients know how to agree to contact investigation.	Yes, lay health workers lack skills to elicit TB symptoms from contacts during TB screening.	No, most contacts already have the strength and skills to do this.
Psychological capability	Yes, index patients lack knowledge about TB to understand the need for contact tracing.	No, lay health workers know how to carry out home visits for screening.	Yes, some contacts cannot remember to follow-up in clinic and do not understand the risk of TB.
Physical opportunity	Yes, clinics lack space for private conversations between index patients and household contacts.	Yes, lay health workers are not able to find every household contact in the home at the time of the visit(s).	Yes, some contacts lack the time and money to travel to clinic.
Social opportunity	Yes, some index patients feel that they lack authority to consent to contact investigation, especially if not the head of household.	No, clinic workers already trust and encourage lay health workers to perform many TB evaluation activities.	Yes, some contacts need permission from family members to go to clinic.
Reflective motivation	Yes, some index patients do not believe that it is necessary or beneficial to contacts undergo TB screening and evaluation.	No, lay health workers already believe they can and should play this role.	Yes, some contacts do not wish to follow-up in clinic because they do not believe that it is necessary or valuable.
Automatic motivation	Yes, some index patients fear stigma from the household or community if a health worker visits the home for contact investigation.	Yes, some lay health workers are afraid of contracting TB.	Yes, some contacts are afraid to go the clinic and do not trust health workers.
Intervention functions	Education, Persuasion, Modeling, Environmental restructuring, Enablement.	Education, Training, Persuasion, Environmental restructuring, Enablement, Incentivization.	Education, Training, Persuasion, Environmental restructuring, Enablement, Incentivization.

COM-B, Capability, Opportunity, and Motivation determinants of Behavior framework; TB, tuberculosis.

For each of the three required behaviors for TB contact investigation, the table presents answers to the question, “Is change needed for the key behaviors to occur?” We provided answers to this question considering each of the six theoretical determinants of behavior specified by the COM-B model, drawing on focus group discussions with and/or direct observation of the core participants in contact investigation, who include lay health workers, index patients, and contacts. Finally, the list of all intervention functions appropriate to the identified COM-B determinants are drawn from published matrixes that list all intervention functions that might fit the identified determinants (36).