The question of improved data for planning is of great importance. If a country's economic and social services are to be geared to serving the population as a whole, they should be developed in accordance with existing patterns and the possibilities for acting on them. The achievement of high response rates is of great importance in survey research. Confident generalizations can be made about the universe of study only if probability sampling has been adhered to and a high level of response obtained.
Social and demographic statistics are inadequate for many reason. Suppliers of information may falsify reports. People interviewed may answer questions inaccurately because they do not understand the questions or they feel answering may jeopardize them in some way. Different and seemingly comparable sets of information may differ because of differences in the time frame when the information was gathered, what kind of questions were asked, and who asked them. Statistics can and frequently are misinterpreted.
In 1991 it was reported by the UN that in compiling its Demographic Yearbook, 102 out of 205 countries or areas considered that their birth registration was complete, and 95 countries or areas indicated complete death registration. The remaining countries either indicated that they consider their birth or death registration less than 90% complete or provided no information at all. Marriage, divorce and foetal death statistics had different degrees of coverage. These figures are considered an improvement on the situation in 1950 when out of 144 countries, only 52 and 53 countries respectively completed birth and death registration. The quality of vital statistics continues to be considered unsatisfactory and is especially weak with respect to causes of death.
If governments and the international community want improvement, then they must be able to measure change to see whether current policies are effective. At a minimum, the basic indicators of social progress – malnutrition, primary school attendance, survival to age 5, contraceptive use rate – must be measured yearly. For now, the UN agencies and the World Bank publish different statistics, based on different methods of interpreting the figures. An international agreement for establishing and using common key indicators would enable Third World countries to begin to break the link between poverty and the lack of statistics.