A manual for impact assessments. The SCH Practical and Precision Assessment (SPPA) strategy is an evidence-based approach for conducting impact assessments for SCH. The SPPA was identified by programme managers and SCH experts from the African region as a feasible and sufficiently accurate approach after reviewing and discussing the results of a multi-country study. This manual describes the resulting Practical and Precision Assessments approach and includes a discussion of the underlying concepts, factors to consider when determining what approach is appropriate, and how to interpret the collected data. The manual also includes annexes with standard operating procedures for conducting the stool and urine analyses.