Statistical Issues - World Tables

A concerted effort has been made to standardize data and to note exceptions to standards. However, full comparability cannot be ensured, and care must be taken in interpreting the indicators. The data are drawn from sources thought to be most authoritative, but many of them are subject to considerable margins of error. This is particularly true for the most recent year or two, since conventional statistical reports take time to digest.

Moreover, intercountry and intertemporal comparisons always involve complex technical problems, which have no full and unequivocal solution.

The statistical systems in many developing economies are weak, and this affects the availability and reliability of the data. Readers are urged to take these limitations into account in interpreting the indicators, particularly when making comparisons across economies. World Tables addresses issues of data reliability partly by omitting questionable estimates but also by flagging methodological issues that can influence analysis.

Country pages for about ten Bank members have been omitted for lack of adequate data; some time series on other country pages are blank or uncertain.

Unless otherwise stated, data are reported for calendar years.