Public health triangulation: approach and application to synthesizing data to understand national and local HIV epidemics.

BACKGROUND: Public health triangulation is a process for reviewing, synthesising and interpreting secondary data from multiple sources that bear on the same question to make public health decisions. It can be used to understand the dynamics of HIV transmission and to measure the impact of public health programs. While traditional intervention research and meta-analysis would be ideal sources of information for public health decision making, they are infrequently available, and often decisions can be based only on surveillance and survey data. METHODS: The process involves examination of a wide variety of data sources and both biological, behavioral and program data and seeks input from stakeholders to formulate meaningful public health questions. Finally and most importantly, it uses the results to inform public health decision-making. There are 12 discrete steps in the triangulation process, which included identification and assessment of key questions, identification of data sources, refining questions, gathering data and reports, assessing the quality of those data and reports, formulating hypotheses to explain trends in the data, corroborating or refining working hypotheses, drawing conclusions, communicating results and recommendations and taking public health action. RESULTS: Triangulation can be limited by the quality of the original data, the potentials for ecological fallacy and "data dredging" and reproducibility of results. CONCLUSIONS: Nonetheless, we believe that public health triangulation allows for the interpretation of data sets that cannot be analyzed using meta-analysis and can be a helpful adjunct to surveillance, to formal public health intervention research and to monitoring and evaluation, which in turn lead to improved national strategic planning and resource allocation.

The use of epidemiological data to inform the PEPFAR response.

The history of the HIV epidemic and the response to the epidemic is fundamentally a history of an emergency response to a global crisis. Trends and projections from initially available data were instrumental in establishing the President's Emergency Plan for AIDS Relief (PEPFAR) and in determining the direction of the program. Additionally, PEPFAR was built on data and the potential impact of interventions, and required the constant monitoring of the epidemic to report on the progress of the program. The response to the HIV epidemic saw the development of international guidelines and recommendations for data collection and epidemiological modeling. Although it is true that the urgency of the response often meant that data from data-poor countries suffered from incompleteness and bias, fortunately, as the response matured, the quality of the data and the infrastructure supporting data collection also matured. PEPFAR investments in surveillance and surveys were and remain critical for responding to the epidemic. The future of the response is reflected in growing country capacities to collect valid and reliable data, and using those data for decision making.