Using lot quality assurance sampling to assess measurements for growth monitoring in a developing country's primary health care system

Background. Local supervisors used lot quality assurance sampling (LQAS) during routine household visits to assess the technical quality of Costa Rican community-based health workers (CHW): measuring and recording weights of children, interpreting their growth trend, and providing nutrition education to mothers. Method. Supervisors sampled 10 households in each of 12 Health Areas (4-8 hours per area). No more than two performance errors were allowed for each CHW. This LQAS decision rule resulted in judgements with a sensitivity and specificity of about 95%. Results. Three categories of results are reported: (1) CHW adequately weighed children, calculated ages, identified children requiring nutritional services, and used the growth chart. (2) They needed to improve referral, education, and documentation skills. (3) The lack of system support to regularly provide growth cards, supplementary feeding to identified malnourished children, and other essential materials may have discouraged some CHW resulting in them not applying their skills. Conclusions. Supervisors regularly using LQAS should, by the sixth round of supervision, identify at least 90% of inadequately performing CHW. This paper demonstrates the strength of LQAS, namely, to be used easily by low level local health workers to identify poorly functioning components of growth monitoring and promotion.