Women in World Christianity Project

In 2019, Dr. Zurlo received a Louisville Institute Project Grant for Researchers for a ground-breaking project on studying women in World Christianity. Demographers, social scientists, historians, and scholars of other disciplines have stated for decades that women are “more religious” than men. Yet, there exists very little hard data on women in global Christianity. Demographers estimate that world Christianity is majority female, but have no comprehensive, global data to back up that claim. The Women in World Christianity Project aims to fill this gap and adequately report on the status of the world Christian movement by providing up-to-date information on the percentage female of every Christian denomination in every country of the world. This project also received funding from the Constant H. Jacquet Research Award from the Religious Research Association.

Dr. Zurlo’s book on the subject will be released in 2023 – Women in World Christianity: Building and Sustaining a Global Movement (Wiley-Blackwell).


Dr. Zurlo’s dissertation is about the life and work of David B. Barrett (1927–2011), who arrived in Nairobi, Kenya as a missionary with the Church Missionary Society in 1956 in the midst of nationalist movements leading up to the demise of British colonialism. Barrett was a trained aeronautical engineer, ordained Anglican priest, and held a doctorate in the Sociology of Religion. He started his work by doing field surveys of church affiliations in Kenya, but his research quickly expanded to encompass religious affiliations of all types throughout Africa and eventually worldwide. In the process, he established the Unit of Research of the Church of the Province of East Africa in Nairobi in 1965. After thirteen (1968–1981) years of research and travel to 212 countries, Barrett’s work culminated in the 1982 World Christian Encyclopedia (WCE), published by Oxford University Press. The WCE contained information on some 22,000 Christian denominations in every country of the world and was hailed by the media, scholars, and missions communities as a vital resource. Barrett’s work represents a shift in thinking from missionary statistician to professional religious demographer. Until now, his life and work have never been researched to see what impact he had on the development of religious demography as an academic discipline—arising from a long tradition of missionaries as sources of scientific data—as well as our contemporary understanding of world Christianity.

Her monograph will be released in early 2023 with Brill: From Nairobi to the World: David B. Barrett and the Re-Imagining of World Christianity.


“Religious demography” is defined as the scientific and statistical study of the demographic characteristics of religious populations, primarily with respect to their size, age-sex structure, density, growth, distribution, development, migration, and vital statistics, including the change of religious identity within human populations and how these characteristics relate to other social and economic indicators. In this sense, we go beyond basic demographic features of religion (age, sex, fertility, mortality) and look at religion as a demographic characteristic of human populations deserving its own field of inquiry. Dr. Zurlo’s research on world religions and Christian denominations contributes to both the World Christian Database and World Religion Database. 

The International Religious Demography Project at Boston University, where Dr. Zurlo works as Research Associate, provides a venue for the cross-validation of religious demography sources, reconcile conflicting sources of data and determine the best sources for countries where data are in short supply. The project compares cross-tabulated adherent data from demographic and health surveys, census data, and other social science sources with other demographic information such as age, level of religious participation, and so forth. However, survey and census data are lacking for many countries of the world. To make estimates for countries where such data is absent, the International Religious Demography Project has the capacity to analyze the Center for the Study of Global Christianity’s unsurpassed collection of religious membership data, as well as draw on its extensive ethnolinguistic data, which provides an alternative method to estimate the size of religious groups in countries for which religious adherent data are not available.