For statistical data from different countries to be useful in international planning of economic and social development, this data must be collected, analyzed and presented in such a way as to permit inter-country comparisons. Despite considerable progress, it is still very difficult to prepare regional and world totals on the basis of information originating from official national sources. Each country may apply a slightly different method of data collection such that each individual statistical figure requires a special qualifying footnote in any international statistical compendium. Another source of incomparability is vast differences in meaning for terms, such as, unemployment, disease and crime.
Of paramount importance are national economic, social and health statistics, which despite their intense study at international levels cannot be subsumed into comprehensive regional or global aggregates to detect levels and trends. Employment, distribution of wealth, crime, human rights and educational statistics are among those presenting difficulties.
The timidity of academicism or some professional statisticians employed by intergovernmental organizations prevents them from assembling probabilistic data, or to engage in forecasting to any considerable extent. In some cases, country data submitted is suppressed from publication because its statistical treatment does not conform to that of the majority of countries, or there is some anomaly or marginally higher level of statistical uncertainty.