The first step in the process is to proactively seek out all possible sources of data, including vital registration systems, national censuses, household surveys conducted by global programmes, and multi-purpose surveys conducted without international sponsorship.
To seek out national data sources that might be overlooked, UNICEF conducts an annual exercise called the Country Reports on Indicators for the Goals (CRING). CRING gathers recent information for all indicators regularly reported on by UNICEF, including the infant and under-five mortality rates.
Different data sources and calculation methods often yield widely differing estimates of infant mortality for a given time and place. In order to reconcile these differences, UNICEF developed, in coordination with WHO, the WB and UNPD, an estimation methodology that minimizes the errors embodied on each estimate and harmonize trends along time. Since the estimates are not necessarily the exact values used as inputs for the model, they are often not recognized as the official IMR estimates used at the country level. However, as mentioned before, these estimates minimize errors and maximize the consistency of trends along time. Applying a consistent methodology also allows comparisons between countries, despite the varied number and types of data sources.
After plotting all available values for infant and under-five mortality, analysts use weighted least squares to fit a multi-spine regression line to the data points and extrapolate the trend to the present. The use of weights allows analysts to make a judgment about the relative quality of each data set and how representative it is likely to be of the population. The last step is to decide which set of estimates (for infant mortality or under-five mortality) is more consistent and to use a model life table to derive the other set of estimates from it.
Additional details of the methodology are available in the following working paper: UNICEF, WHO, The World Bank and UN Population Division, ‘Levels and Trends of Child Mortality in 2006: Estimates developed by the Inter-agency Group for Child Mortality Estimation’, New York, 2007.
||CRING is the Country Reports on Indicators for the Goals and is produced at the country level every year to update UNICEF’s database. Each year, UNICEF’s executive director sends out a request for information to all of the organization’s regional directors and country representatives, who are stationed in over 150 countries around the world. They are asked to update the data already available at headquarters by submitting new values for each indicator along with copies of the original source documents, such as survey reports.
||These agencies have created the Inter-agency Group for Mortality Estimation (IGME).
||This methodology is better described in: K. Hill, R. Pande and G. Jones, Trends in child mortality in the developing world: 1990 to 1995, UNICEF staff working papers, Evaluation, Policy and Planning Series, UNICEF, New York, 1997.