Sohal et al1 have attempted to evaluate the public health and economic impact of incentivised primary care services on sexually transmitted infection (STI) diagnoses across a population. In doing so, they have illustrated the difficulties in obtaining information that bedevil the planning of sexual health services in the United Kingdom2 3 and elsewhere.4

A key public health motive for developing such services is the provision of improved access to testing and care. This should be measured in terms of outcomes with potential impact on transmission dynamics, particularly the duration of infectivity.5 How can we tell whether this has been achieved? Measures of access, detailed …