Conversion growth of Protestant churches in Thailand

M Visser

Research output: ThesisDoctoral thesis 2 (Research NOT UU / Graduation UU)


This study set out to answer the question what factors are conducive for church growth through conversion in Protestant Thai churches. After 180 years of unhindered Protestant missionary activity only 0.3% of ethnic Thai, about 185,000 people, have become Protestants. Though small, ethnic Thai Protestantism has shown a rather high annual growth rate of 4.4% over the last three decades. This consists of 0.9% biological growth and 3.5% conversion growth. The personal background of people proved to be a predictor of conversion probability, yet the more striking finding was that persons from all different social groups were becoming Christians. One interesting finding is that old people are slightly more likely to convert than young people. This shows that conversion to Protestantism in Thailand is not driven by the modernization process and therefore lacks one of the most important push factors that results in rapid Protestant growth in some other countries. A very important finding is that relatives of Christians are hundreds of times more likely to become Christians than the general population. This confirms that among ethnic Thai pull factors are quite strong. Once people have Christians in their close social network there is a rather large chance that they become Christians as well. Yet push factors are almost absent. If Christianity is not present in their inner circle there is little or no impetus to seek an alternative to their present religion.

Another subquestion addressed in this study was what kind of churches grow through conversion growth. The most important variable, trumping all others, is the age of a local church. Younger churches attract more new Christians. The continued growth of Protestantism in Thailand is tied to a vigorous planting of new churches. It makes a difference what kind of new churches are planted. The second main variable is traditionalism. Traditional churches, with a lot of church rules and emphasis on the role of the clergy, are less likely to grow. This is in line with the finding that the conversion of most new Christians is influenced by people in their own social network. A church that empowers its members is a church that will grow. These two variables together explain 80% of all variance in conversion growth.

This study has some wider implications for the study of conversion and church growth. It shows that making a reliable count of the number of churches and Christians in a country is not impossible. Methodologically a new way was developed to measure conversion church growth. A time analysis of survey data, combined with census data, makes it possible to say something about conversion growth, biological growth, and the retention rate of children born in Christian families. This is a valuable tool that could profitably be used more often in missiology and the sociology of religion. Statistical modelling of conversion church growth showed which variables were independently important, and which were redundant. This brought about a clear picture of the important predictors of conversion church growth. In this way it is shown that modelling, which so far has been virtually absent in missiology, is an important tool.

Original languageUndefined/Unknown
QualificationDoctor of Philosophy
Awarding Institution
  • Utrecht University
  • Jongeneel, J.A.B., Primary supervisor, External person
  • Phaituncharoenlap, M., Supervisor, External person
  • Philips, M.G., Supervisor, External person
Award date24 Oct 2008
Place of PublicationZoetermeer
Print ISBNs9879023923275
Publication statusPublished - 24 Oct 2008


  • General theory
  • Sociale verandering, sociale processen en sociale conflicten
  • Godgeleerdheid
  • Social structure and institutions (Groups, etc.)
  • Overig maatschappelijk onderzoek
  • Godgeleerheid (GODG)

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