Technical notes (on page 331) provide information detailing the specific data sources for key indicators as well as guidance for the interpretation of the statistics. Official United Nations estimates are used for all MDG indicators. These figures are supplemented, as necessary, by additional standard data sources. Information on social and political contexts and policy priorities have been obtained from UNFPA country offices and standard United Nations reports. National statistics may differ from the UN estimates due to delays in reporting or incorporation of new estimates into UN databases, application of methodologies adjusting data to increase cross-country comparability and use of non-standard methodologies. Any discrepancies deserve attention in the formulation of national programme strategies and.