World Christian Encyclopedia is a reference work, with its third edition published by Edinburgh University Press in November 2019.
The WCE is known for providing membership statistics for major world religions and Christian denominations including historical data and projections of future populations.
With George Kurian, Barrett and Johnson produced the second edition of the World Christian Encyclopedia, in 2 volumes, in 2001 (Oxford University Press).
[4] Johnson and Zurlo are co-directors of the Center for the Study of Global Christianity at Gordon-Conwell Theological Seminary (South Hamilton, MA, USA).
[6] Margit Warburg, a Danish researcher, has argued that the database contains numerical inaccuracies in its statistics on the Baháʼí Faith.