This article describes criteria used by several organizations to select technologies for assessment and the factors that are common to most lists of criteria. It presents a framework or model (called TAPSS) that relates the most important factors. The model can be used to estimate the expected impact of an assessment on health and economic outcomes for a population. It incorporates information on such factors as the health and economic importance of the disease addressed by the technology, the expected impact of the technology on health and economic outcomes, variations in the technology's current use, and factors affecting the production and reception of an assessment. The article includes an example of an application of the method—screening for maple syrup urine disease.