With the advent of the UN Literacy Decade launched in 2003, there is increased emphasis on monitoring and evaluation of adult literacy around the globe. The present paper presents an overview of the main approaches that have been taken to measure adult literacy within and across countries. A particular focus of the present review is to compare and contrast three models of literacy assessment: (1) the "traditional" model based largely on census enumeration, which has been used over recent decades to collect national and regional rates of illiteracy; (2) the large-scale survey techniques employed with the International Adult Literacy Survey and similar models; and (3) an intermediate type of assessment that borrows from the previous two models, and attempts to "tailor" the size and complexity of the survey methodology to the policy questions needing answers (called the SQC model). The present paper suggests that there is no single model or set of methods that are universally appropriate to monitoring and measuring in adult literacy around the world, but that blending both programmatic and comparative models through the SQC approach may bring greater involvement in, and insight into, adult literacy evaluations.