Direct observation of patients taking their medication is a strategy to imp
rove completion rates for tuberculosis treatment, but the programmes to imp
lement this approach consist of a complex array of inputs aimed at influenc
ing adherence. Policy makers need a clear understanding of these inputs to
succeed. We systematically identified and reviewed published reports of dir
ect observation therapy (DOT) programmes and compared inputs with WHO's sho
rt-course DOT programme. DOT programmes frequently consist of more than the
five elements of WHO's strategy, including incentives, tracing of defaulte
rs, legal sanctions, patient-centred approaches, staff motivation, supervis
ion, and additional external funds. Focusing on direct observation as a key
factor in the promotion of adherence seems inappropriate. Multiple compone
nts might account for the success of DOT programmes, and WHO should make th
ese explicit.