The DAPA Measurement Toolkit is a free online resource developed to help researchers, public health professionals, and others assess diet, anthropometry, and physical activity. It supports users in understanding existing data and selecting measurement methods suited to their research or practical needs. Rather than endorsing particular methods or instruments, the Toolkit presents information to help users evaluate options and make informed decisions.

Its content covers core concepts such as validity, reliability, measurement error and bias, feasibility, data processing, and statistical assessment. Dedicated sections on dietary assessment, physical activity assessment, and anthropometry explain subjective and objective methods, harmonisation, and relevant measurement indices. Decision matrices help users compare approaches, while video guides demonstrate measurement procedures. An instrument library provides a searchable catalogue of data-capture tools.

The Toolkit also offers updates, related resources, and links to other measurement toolkits, including Nutritools and the NCI/NIH Dietary Assessment Primer. Managed by the MRC Epidemiology Unit, it welcomes feedback from users.