Summary

This article describes the mechanism used by the multiple-country Global Trachoma Mapping Project (GTMP) to maximise the accuracy and reliability of its outputs. Using expert opinion, computer simulation, working groups, field trials, progressively accumulated in-project experience, and external evaluations, the GTMP developed: 1) criteria for where and where not to undertake population-based prevalence surveys for trachoma; 2) three iterations of a standardized training and certification system for field teams; 3) a customised Android phone–based data collection app; 4) comprehensive support systems; and 5) a secure end-to-end pipeline for data upload, storage, cleaning by objective data managers, analysis, health ministry review and approval, and online display. The experience of the GTMP shows that it is possible to quality control and quality assure prevalence surveys in such a way as to maximise comparability of prevalence estimates between countries and permit high-speed, high-fidelity data processing and storage, while protecting the interests of health ministries.