Accessing and/or surveying most-at-risk populations can be challenging. Consequently, data obtained may not be based on a representative sample of the national, most-at-risk population being surveyed. If there are concerns that the data are not based on a representative sample, these concerns should be reflected in the interpretation of the survey data. Where different sources of data exist, the best available estimate should be used. Information on the sample size, the quality and reliability of the data, and any related issues should be included in the report submitted with this indicator.

The inclusion of these indicators for reporting purposes should not be interpreted to mean that these
services alone are suffi cient for HIV prevention programmes for these populations. The set of key interventions described above should be part of a comprehensive HIV prevention programme, which also includes elements such as provision of HIV prevention messages, (e.g. through outreach programmes and peer education), treatment of sexually transmitted diseases, opioid substitution therapy for injecting drug users, and others. For further information on the elements of comprehensive HIV prevention programmes most-at-risk populations please see the Practical Guidelines for Intensifying HIV Prevention: Towards Universal Access.

This indicator asks about services accessed in the past 12 months. If you have data available on another time period, such as the last 3 or 6 months or the last 30 days, please include this additional data in the comments section of the reporting tool.

It has been recommended that the issue of quality and intensity of reported services among most-at-risk
populations be addressed more explicitly in terms of criteria for the measurement of the components of
provided services. Taking into account the complexity of this element of measurement, particularly within
the context of most-at-risk populations, the development of such criteria requires an intensive process of
information gathering, synthesis and recommendations formulation. This process was initiated in 2008 and will inform the review of the UNGASS reporting system which is scheduled for 2010. In the meantime, it is recommended that the guidelines mentioned below be referred to as reference documents that can facilitate interpretation of the collected data from a quality and intensity perspective.

To maximize the utility of these data, it is recommended that the same sample used for the calculation of
this indicator be used for the calculation of the other indicators related to these populations.