How are revisions managed?
Historical data in the World Development Indicators (WDI) database may change with each database update. We advise users to use our most current data set, since it provides data for the latest year available and also includes any revisions to previously published data. In most cases, revisions are due to improvements in the estimates, due to better collection methods and more recent surveys. Improvements in methodology or data sources are also possible. In certain instances, data which have been determined to be no longer robust may be deleted.
Each new edition of WDI contains the most complete time-series we have currently available, and gap-filling from previous editions is inadvisable. In very few cases, revisions to certain time-series may cause discontinuities in series which cannot be reconciled by linking or other estimation techniques.