Dental Hygiene Recall Interval Elasticity and Caries Arrest in Ghanaian School Programmes: A Regression Discontinuity Analysis of Scheduling Thresholds

School-based dental hygiene programmes in Ghana assign recall intervals using scheduling thresholds that are rarely evaluated for their caries-arrest consequences. The estimand is the local average treatment effect at each threshold, identified from the discontinuity in recall assignment among children whose caries-risk scores fall just above and just below the cut-points. Because no primary data were collected for this analysis, the paper develops the identification argument, the estimation equation and the falsification tests that a field implementation would require, and it calibrates the expected precision of the design using published variance components from comparable school programmes. The contribution is a methodological template that converts administrative scheduling rules into a source of quasi-experimental variation, allowing programme managers to estimate whether shortening recall intervals produces caries arrest gains large enough to justify the additional hygiene-therapist time. The paper also derives the conditions under which threshold-based scheduling generates selection bias, and it specifies the bandwidth and donut-hole choices that would preserve internal validity in a Ghanaian school setting.