Medicine counter-task-shifting of dental hygiene therapy caries screening into antenatal care and referral completion in Tanzanian clinics: a difference-in-differences analysis

Tanzanian antenatal care (ANC) clinics record the cadre of the provider who delivers each visit, and the DHS Program indicator 'Antenatal care provider: Doctor' (RH_ANCP_W_DOC) captures the share of ANC visits led by a doctor across 38 African countries between 1986 and 2025. the present analysis treats that indicator as the empirical anchor for a methodological argument about counter-task-shifting: the proposal that dental hygiene therapists, rather than doctors, should absorb caries screening within ANC and route positive screens to treatment. Because no trial of that proposal exists, the paper specifies a difference-in-differences design that would identify the effect of counter-task-shifting on referral completion, and it characterises the outcome distribution that any such design must confront. Across 549 country-survey observations the indicator had a mean of 15.06 (SD 16.47), ranging from 2.22 in Burkina Faso to 65.62 in Egypt. The distribution is right-skewed and heterogeneous across countries and survey years, which implies that a naive pre-post comparison would confound counter-task-shifting with secular ANC staffing trends. The paper derives the identifying assumptions, the parallel-trends diagnostic, the clustering structure and the minimum detectable effect that a Tanzanian pilot would need, and it argues that the contribution of counter-task-shifting scholarship lies less in estimating an average effect than in specifying the referral-completion mechanism that a difference-in-differences design can credibly test.