An Empirical Study on the Determinants of Christian Growth Rate

Cheol-young Lee

Head of the International Affairs Research Association

Abstract

This study empirically analyzed the factors influencing Christian growth rates using cross-sectional data from 180 countries as of 2016. Through correlation analysis, multiple regression, and logit regression, it examined how demographic, political–social, and economic–cultural factors affect Christian growth. The results indicate that population growth rate consistently emerges as the strongest explanatory variable, while political stability also exerts a positive influence. In contrast, social hostility functions as a suppressive factor for Christian expansion. The Government Restrictions Index showed a weak effect in simple correlations but demonstrated a positive impact in multiple regression analyses, suggesting the so-called “persecution–growth paradox.” Contrary to expectations, economic and educational factors did not exhibit clear positive effects; notably, in Christian-majority countries, higher educational attainment was associated with lower church growth rates. Urbanization and internet penetration likewise appeared as strong secularizing forces in Christian-majority contexts. Finally, the evangelization rate promoted growth when below 4%, showed stagnation in the 4–10% range, and beyond this threshold, other social and political factors exerted greater influence. This study questions the traditional 2% criterion and suggests that contemporary mission strategies should move beyond universal benchmarks, adopting context-specific approaches tailored to the realities of individual countries and peoples.

1. Introduction

The global landscape of Christianity in the twenty-first century is undergoing an unprecedented transformation. In the West—particularly in Europe and North America—church attendance continues to decline, secularization has deepened, and the social influence of the church has steadily weakened. In contrast, Christianity has been expanding explosively in Africa, Asia, and Latin America, forming new centers of vitality. This phenomenon is often described under the concept of “World Christianity,” highlighting the accelerating shift of Christianity’s center of gravity from the West to the Global South (Sanneh, 2003). Jenkins (2011) projected that while Africa had approximately nine million Christians in 1900, the number had exceeded 300 million by 2000 and would make Africa the center of global Christianity by 2050. According to Zurlo et al. (2020), Christians accounted for 34.5% of the world’s population in 1900, 32.4% in 2000, and 32.2% in 2015; however, this proportion is expected to rise slightly to around 35% by 2050. The reason is that the pace of revival in the Southern Hemisphere is outstripping the rate of decline in the Northern Hemisphere. In sub-Saharan Africa, high fertility rates are a major driver, while in parts of Asia—such as China, India, Cambodia, and Mongolia—conversion growth has become a key contributing factor.

Across nations and peoples, the Christian population both increases and decreases. Yet there remain ongoing debates about where and under what conditions Christian growth or decline occurs. Since the mid-twentieth century, Donald McGavran and other missiologists have studied the factors influencing church growth, but most of this research has relied heavily on case studies and descriptive analyses. Above all, the lack of reliable statistical data has been a major limitation to empirical research. For instance, in the case of China, the Pew Research Center (2020) estimated that Christians made up approximately 2% of the total population (around 25 million people). In contrast, Hackett and Tong (2023), after reviewing 19 nationally representative surveys conducted since the early 2000s, concluded that there was no clear evidence of a continuous increase in the Christian share of China’s population. Conversely, Stark and Wang (2015) predicted that Christianity in China would grow by 7% annually over the coming decades, reaching 580 million believers by 2040. Such discrepancies are not unique to China but may reflect a broader pattern commonly observed in many mission fields.

Nevertheless, the question “What factors exert a significant influence on Christian growth rates?” remains crucial from both missiological and practical perspectives. To address this, the present study employs data from 180 countries as of 2016 to quantitatively analyze the demographic, social, political, and cultural determinants of Christian growth. Specifically, nine variables are examined: population growth rate, government restrictions on religion, social hostility toward religion, political stability, educational attainment, economic growth rate, urbanization rate, internet penetration, and evangelization rate.

This study carries twofold academic and practical significance. First, by empirically testing the validity of multiple explanatory variables, it evaluates the usefulness and limitations of these indicators as tools for formulating mission strategies. Second, by providing an empirical analysis of global Christian growth patterns, it identifies multidimensional factors influencing such growth and offers insights that may guide the strategic planning of missionary activities. Ultimately, this study seeks to answer the following key questions: What demographic, social, political, and cultural factors determine Christian growth rates? and Can the evangelization rate serve as a valid indicator for explaining such growth? These questions go beyond academic curiosity; they hold direct implications for the allocation of global church resources and the formulation of missionary strategies.

2. Theoretical Discussion and Hypothesis Development

2.1 Demographic Factors

Changes in religious populations are not merely the result of individual faith choices but are closely linked to structural demographic conditions. Kaufmann (2010) argued that groups with higher fertility rates expand their political and cultural influence over time, referring to this phenomenon as a “demographic game of religion.” In regions such as sub-Saharan Africa, where the fertility rate exceeds four children per woman, churches have been growing explosively. This suggests that beyond active missionary endeavors, the demographic foundation itself constitutes a major driving force of church expansion.

According to Johnson and Zurlo’s World Christian Database (2015), a substantial portion of the global increase in Christian population over the past fifty years occurred in high-fertility regions. This finding indicates that demographic shifts resulting from high fertility represent an important pathway for religious growth. While demographic factors do not guarantee qualitative church development, numerous studies confirm that they have been among the most powerful and consistent variables explaining religious growth rates.

Hypothesis 1: The higher the population growth rate, the greater the growth rate of Christianity.

2.2 Political and Social Factors

Boyd-MacMillan (2019) argued that when governments restrict religious freedom, religious conflict tends to intensify and growth is suppressed. He contended that persistent persecution across generations makes it difficult for churches to survive, and when society as a whole becomes hostile to Christianity, the church gradually declines. Conversely, the so-called “persecution–growth paradox” maintains that persecution may in fact strengthen the cohesion of religious communities. The early Church Father Tertullian famously stated, “The blood of the martyrs is the seed of the Church,” implying that oppression and persecution do not destroy the church but rather accelerate its revival. Indeed, the growth of the Iranian church has continued despite decades of severe state repression, demonstrating that institutional persecution does not necessarily lead to the inhibition of religious expansion. Thus, governmental restrictions on religion may exert both suppressive and reinforcing effects simultaneously.

Hypothesis 2: Governmental restrictions on religion have dual effects on Christian growth rates, either suppressing or, in certain contexts, promoting growth.

Fox (2008) showed that social hostility can serve as an even greater barrier than formal legal restrictions imposed by governments. Even when the state does not institutionally regulate religious activities, internal discrimination and exclusion within communities can structurally constrain the spread of churches. In many Muslim-majority societies, converts face intense social pressure from family and community members and may encounter occupational disadvantages, social isolation, or even violence. Such experiences restrict personal religious choice and weaken the social receptivity necessary for new churches to take root. Consequently, social hostility functions not merely as a source of personal discomfort but as a structural factor that impedes the institutional growth of churches and thereby suppresses Christian expansion.

Hypothesis 3: The greater the level of social hostility, the lower the growth rate of Christianity.

Norris and Inglehart (2004) argued that political and economic instability can heighten personal religiosity; however, in terms of institutional church growth, stability is a more decisive factor. Although social instability may intensify spiritual yearning, institutional foundations such as church planting, seminary operation, and long-term missionary deployment become difficult to sustain. Civil wars, regime changes, and economic crises disrupt the consistency and institutionalization of religious activity, severely limiting the sustainability of growth. Conversely, a stable political system provides the foundation for long-term planning and organizational expansion, even when full religious freedom is not guaranteed by law.

Hypothesis 4: The higher the level of political stability, the greater the growth rate of Christianity.

2.3 Economic and Educational Factors

In his classic work The Protestant Ethic and the Spirit of Capitalism (1905), Max Weber argued that religion promoted economic development; however, contemporary sociology often emphasizes the reverse causal pathway. Inglehart and Welzel (2005) suggested that economic prosperity alleviates existential insecurity, thereby reducing the perceived need for religion. Western Europe, for instance, has experienced rapid secularization in parallel with economic growth. Yet in several Asian contexts, such as South Korea, both economic development and church growth have occurred simultaneously, illustrating that the relationship between economy and religion is not linear. At the early stages of development, churches may serve as vital sources of social capital and expand alongside economic progress, but beyond a certain threshold, secularization tends to dominate.

Hypothesis 5: At the early stages of development, higher economic growth rates are associated with increased Christian growth rates; however, beyond a certain threshold, higher economic growth rates are associated with a decline in Christian growth.

The effects of education are also ambivalent. Berger and Davie (2008) argued that the spread of higher education strengthens rationalism and critical thinking, thereby weakening traditional religious belief and accelerating secularization. Indeed, in Western societies, rising educational levels have been closely linked to declining church attendance and growing religious indifference. On the other hand, schools and universities founded by missionaries in Africa and Asia became not only centers for knowledge dissemination but also key institutions for transmitting Christian values and worldviews. These institutions played a decisive role in developing local leadership and establishing the organizational foundations of the church (Gallego & Woodberry, 2010). Thus, education can act both as a structural factor leading to religious decline and, in certain contexts, as a strategic tool that fosters Christian expansion and institutional growth.

Hypothesis 6: At the early stages of development, higher educational attainment increases Christian growth rates; however, beyond a certain threshold, higher education levels decrease Christian growth rates.

2.4 Cultural and Technological Factors

Wilson (1982) argued that urbanization weakens religiosity because urban pluralism and anonymity undermine religious authority and communal bonds. In contrast, Stark (1997) emphasized that cities can serve as fertile ground for new religious movements. Early Christianity, for example, spread rapidly through major urban centers of the ancient Mediterranean world, and in modern times, Pentecostal and charismatic movements have proliferated among urban poor populations (Martin, 2002). Hence, urbanization may simultaneously promote secularization and provide opportunities for religious innovation.

Hypothesis 7: At the early stages of development, higher urbanization rates increase Christian growth rates; however, beyond a certain threshold, higher urbanization rates decrease Christian growth rates.

The expansion of the internet and digital media simultaneously challenges traditional religious authority and enables new forms of mission and community (Campbell & Tsuria, 2021). Digital spaces allow individuals to practice faith in personalized and decentralized ways, transcending hierarchical church structures and physical limitations. Yet this also reshapes clergy–laity relationships, worship patterns, and church administration, potentially weakening institutional loyalty. At the same time, online sermons, Bible study apps, Christian YouTube channels and podcasts, and faith-based social media communities have opened new avenues for evangelism. During the COVID-19 pandemic, online worship through streaming platforms and video conferencing became essential tools for maintaining faith and church continuity, giving rise to a new model of “networked church communities” that transcend physical distance.

Hypothesis 8: Internet penetration has dual effects on Christian growth rates, either reducing or, in certain contexts, enhancing growth.

2.5 Evangelization Rate

The evangelization rate has long been employed as a central indicator in missionary strategy (Winter, 1974). Traditionally, groups with an evangelization rate below 2% were classified as “unreached peoples,” assumed incapable of sustaining indigenous evangelization. However, this criterion has been criticized for lacking sufficient empirical or statistical justification. In practice, evangelization rates do not always correlate linearly with church growth. Generally, a higher evangelization rate implies greater potential for Christian expansion and stronger self-sustaining faith communities. Yet beyond a certain level, growth tends to slow or plateau. Once a threshold is surpassed, the evangelization rate may lose explanatory power as other social and cultural factors exert greater influence. Therefore, strategic use of evangelization metrics requires cautious interpretation.

Hypothesis 9: Higher evangelization rates are associated with increased Christian growth rates, but beyond a certain threshold, growth slows or declines.

2.6 Summary

In summary, population growth is expected to exhibit a consistent positive correlation with Christian growth rates. Governmental restrictions on religion may not produce uniform outcomes but can exert both suppressive and reinforcing effects depending on context. Social hostility is anticipated to show a negative relationship with Christian growth, while political stability should have a positive effect. Economic development, education, and urbanization are likely to facilitate church growth during early stages of modernization but may turn into secularizing influences once a certain level is reached. The internet likewise serves as both a catalyst for evangelization and a factor that undermines institutional religious authority, thus producing dual effects. Finally, the evangelization rate initially shows a strong positive association with growth but tends to stagnate or decline beyond a specific threshold.

3. Research Design and Data

This study empirically examines the factors influencing Christian growth rates using cross-sectional data from 180 countries as of 2016. The unit of analysis is the nation-state, and the dependent variable is the rate of change in the Christian population in 2016. Although Christian growth can be defined in various ways, this study conceptualizes it simply as the increase or decrease in the number of Christians. The data were drawn from the Association of Religion Data Archives (ARDA), using Christian population figures from 2010 and 2020. The Christian population growth rate for 2016 was estimated through interpolation. The mean value of the dependent variable was 0.42%, with the maximum observed in Sudan (10.37%) and the minimum in Libya (–14.8%).

Independent variables include population growth rate, government restrictions on religion, social hostility toward religion, political stability, economic growth rate, education, urbanization, internet penetration, and evangelization rate. These variables encompass the demographic, political–social, economic, and cultural dimensions identified in previous studies as related to Christian growth. Population growth rate data were obtained from the World Bank’s 2016 country-level statistics. The average population growth rate was 1.33%, with Qatar recording the highest (4.6%) and the U.S. Virgin Islands the lowest (–1.96%).

For political and social factors, this study used the Government Restrictions Index (GRI) and Social Hostilities Index (SHI) published by the Pew Research Center in 2016. The GRI consists of 20 indicators measuring the extent to which central and local governments restrict religion (e.g., coercion, physical pressure, administrative control), while the SHI is based on 13 indicators capturing how individuals or social groups infringe upon religious belief and practice (e.g., religion-based crimes, violent incidents, or efforts to restrict specific religious groups). Both indices range from 0 to 10, with higher values indicating stronger government restrictions and higher social hostility, respectively. The mean GRI score was 3.555, with China recording the highest value (8.8) and Guinea-Bissau the lowest (0.3). The mean SHI score was 2.707, with India ranking highest (9.7) and thirteen countries, including Luxembourg, scoring 0. Political stability was measured using the World Bank’s 2016 index assessing the likelihood of political instability and politically motivated violence (including terrorism). The average value was –0.14, with New Zealand as the most stable country (1.5) and Syria as the most unstable (–2.9).

Economic, educational, cultural, and technological variables were also drawn from the World Bank’s 2016 database. Economic growth rate was represented by GDP per capita growth, with a mean of 1.29%, a maximum of 5.44% in Bahrain, and a minimum of –5.27% in South Sudan. Educational attainment was measured by the average years of schooling per capita, with a mean of 8.67 years, the highest being Germany (14.13 years) and the lowest Niger (1.38 years). Urbanization rate ranged from 0 to 100, with a mean of 58.55, Kuwait and Singapore at the maximum (100), and Burundi at the minimum (12.39). Internet penetration, also ranging from 0 to 100, had a mean of 49.1, with Iceland the highest (98.2) and Eritrea the lowest (1.18).

Finally, the evangelization rate was calculated as the proportion of Christians within a country’s total population. While debates persist as to whether this should include only Protestant and Evangelical Christians or also Catholics and Orthodox believers, this study included all Christian traditions. The mean evangelization rate was 50.75%, with the highest in East Timor (99.6%) and the lowest in Afghanistan (0.007%).

The analytical procedure of this study consists of three main steps. First, descriptive statistics were computed to examine the means, standard deviations, minima, and maxima of each variable, thereby identifying the basic characteristics of the sample. Second, Pearson correlation coefficients and partial correlation analyses were conducted to explore the bivariate relationships between Christian growth rates and independent variables. In this process, population growth rate was controlled as a baseline factor to assess the independent explanatory power of the remaining variables. In addition to the baseline model encompassing all 180 countries, two submodels were analyzed: one for Muslim-majority countries (48 cases) and another for Christian-majority countries (101 cases), in order to assess contextual differences by religious composition. Third, multiple regression and logit regression analyses were performed. Multiple regression was used to test the independent effects of each variable while considering all predictors simultaneously. For the logit regression, a dummy variable was created, coded 1 if the Christian growth rate was positive and 0 if negative, to assess the likelihood that each variable influenced the increase or decrease in Christian growth.

Naturally, the study entails certain limitations. Because cross-sectional data at a single point in time were used rather than time-series data, causal relationships between variables cannot be established definitively. Moreover, macro-level national analyses cannot fully capture regional and cultural diversity within individual countries. Nevertheless, a comparative analysis across 180 countries provides valuable empirical insights into the macro-level determinants of Christian growth and offers a foundational dataset for developing global missionary strategies.

4. Research Findings

4.1 Demographic Factors

The population growth rate showed a correlation coefficient of 0.4097 with Christian growth rate, which was statistically significant at the 0.05 level (p = 0). In the social sciences, a correlation coefficient above 0.3 is generally considered meaningful; therefore, this finding suggests that higher population growth corresponds to greater Christian growth. This result supports the study’s first hypothesis, confirming that countries with higher Christian growth rates tend to experience high population growth. The scatterplot (not shown here) visually demonstrates this positive relationship between the two variables. Accordingly, population growth rate was controlled in subsequent analyses to isolate the unique effects of other independent variables, since population growth exerts a strong influence on Christian expansion.

(Relationship between population growth rate and Christian growth rate)

4.2 Political and Social Factors

The Government Restrictions Index (GRI) showed a weak negative correlation (r = –0.1274) that was not statistically significant at the 0.05 level (p = 0.0893). Although marginally significant at 0.1, the relationship was not strong enough to confirm a clear effect as hypothesized. Compared with the robust positive relationship observed for population growth, the GRI effect appears relatively minor. The Social Hostilities Index (SHI) displayed a negative correlation (r = –0.2904, p = 0.0002), indicating that higher levels of social hostility and prejudice are associated with lower Christian growth. The Political Stability Index exhibited a positive correlation (r = 0.3036, p = 0), demonstrating that politically stable countries tend to have higher Christian growth rates. Overall, these findings partially support the study’s hypotheses.

Additional analyses distinguished Muslim-majority (48 countries) and Christian-majority (101 countries) contexts. For the GRI, Muslim-majority countries showed no significant relationship (r = –0.0048, p = 0.9743), suggesting that governmental religious restrictions may suppress Christian growth in some cases but are unrelated—or even positively associated—in others. Christian-majority countries likewise showed no significant relationship (r = 0.0466, p = 0.6449).

By contrast, the SHI in Muslim-majority countries exhibited a statistically significant negative correlation (r = –0.3238, p = 0.0264), while in Christian-majority countries the correlation was weaker (r = –0.1848, p = 0.0656) and not significant at 0.05. This suggests that social hostility constrains Christian growth more severely in Muslim-majority contexts. An interesting pattern emerged for political stability: in Muslim-majority countries the correlation was strongly positive (r = 0.4641, p = 0.001), whereas in Christian-majority countries it was significantly negative (r = –0.3689, p = 0.002). This indicates that the effects of political stability on Christian growth differ depending on religious context.

(Relationship between political stability and Christian growth in Muslim-majority countries)

(Relationship between political stability and Christian growth in Christian-majority countries)

4.3 Economic and Educational Factors

For GDP per capita growth, the correlation coefficient was –0.1086 (p = 0.1479), which was not statistically significant. Separate analyses for Muslim- and Christian-majority countries produced similar results: r = –0.0559 (p = 0.7091) and r = –0.1593 (p = 0.1135), respectively. Thus, contrary to the hypothesis, economic growth and Christian growth did not show a consistent relationship. Some countries experience Christian expansion alongside economic development, while others exhibit decline.

For education, the overall correlation was r = 0.0029 (p = 0.9693), which was not significant. In Muslim-majority countries, the correlation was r = 0.0763 (p = 0.6185), also insignificant. However, in Christian-majority countries, the correlation was strongly negative (r = –0.4501, p = 0), indicating that in societies already highly evangelized, higher education levels correspond to a greater tendency to leave the church.

Taken together, economic and educational factors yielded results partially contrary to the hypotheses. Economic growth alone was not statistically significant, and education showed a negative impact particularly in Christian-majority contexts. These findings suggest that economic and educational variables do not have a simple linear relationship with Christian growth but operate differently depending on religious context and saturation level.

(Relationship between years of schooling and Christian growth in Muslim-majority countries)

(Relationship between years of schooling and Christian growth in Christian-majority countries)

4.4 Cultural and Technological Factors

Urbanization exhibited no significant correlation with Christian growth in the full sample (r = –0.0797, p = 0.2906) or in Muslim-majority countries (r = 0.0074, p = 0.9611). However, in Christian-majority countries, the correlation was strongly negative (r = –0.5117, p = 0), indicating that church disengagement intensifies as urbanization advances in predominantly Christian societies.

Internet penetration followed a similar pattern. Across all 180 countries, the relationship was not significant (r = –0.0848, p = 0.2615); nor was it significant in Muslim-majority countries (r = 0.0143, p = 0.9258). Yet in Christian-majority countries, the correlation was highly negative (r = –0.6848, p = 0), demonstrating that greater internet access corresponds to more pronounced church disengagement.

In summary, urbanization and internet penetration were not significant in the global or Muslim-majority samples but showed strong negative effects in Christian-majority contexts. This contrasts with the initial hypotheses and reflects the secularization tendencies prevalent in Christian-dominated societies.

(Relationship between urbanization and Christian growth in Christian-majority countries)

(Relationship between internet penetration and Christian growth in Christian-majority countries)

4.5 Evangelization Rate

For the entire sample, the correlation between evangelization rate and Christian growth rate was r = 0.2937 (p = 0), indicating that higher evangelization rates are generally associated with greater Christian growth. However, this effect varied across levels of evangelization. Additional analyses divided countries into groups by evangelization thresholds. Among nations with evangelization rates ≤ 2% (28 countries, the “unreached” criterion), r = 0.3919 (p = 0.0432), significant at 0.05 but not 0.01. For countries ≤ 1% (21 cases), the correlation strengthened to r = 0.5445 (p = 0.0131). Countries ≤ 4% (34 cases) also showed a significant positive correlation (r = 0.3618, p = 0.0301). However, for those ≤ 5% (37 cases), the correlation dropped to r = 0.2603 (p = 0.1095) and lost significance. In the 4–10% range, no significant relationship appeared.

In sum, a positive association between evangelization and Christian growth exists primarily in countries with evangelization rates below 4%, suggesting that a minimum Christian presence is necessary for sustained church expansion. Beyond this threshold, Christian growth is no longer explained solely by evangelization rates; other factors—such as social environment, political stability, and cultural context—become more influential.

4.6 Multiple Regression and Logit Regression Analysis

Multiple regression results showed that population growth rate (β = 1.3559), government restrictions (β = 0.0021), political stability (β = 0.0112), and evangelization rate (β = 0.00019) were statistically significant at p < 0.05. The coefficient of determination (R² = 0.3369) indicates that the model explains approximately 33% of the total variance—a meaningful level for social-science data—demonstrating that these variables jointly account for a substantial portion of Christian growth variation.

Importantly, because multiple regression considers all variables simultaneously, its results differ from simple correlations. For example, the GRI showed no clear effect in the correlation analysis but exhibited a positive effect in the regression model: a 1-point increase in government restriction was associated with a 0.21% rise in Christian growth rate. This finding suggests that, beyond suppression, state restrictions can provoke counter-mobilization and strengthen church cohesion. Political stability also emerged as a significant factor, where a 1-point increase in stability corresponded to a 1.12% increase in Christian growth.

Subsequently, a logit regression was conducted by dichotomizing Christian growth (growth = 1, decline = 0). The results identified population growth, internet penetration, and evangelization rate as statistically significant at p < 0.05. Notably, internet penetration produced an odds ratio (OR) of 0.9620, implying that for each one-unit increase in internet access, the odds of Christian growth decrease by 3.8%. This confirms that digital expansion acts as a driver of secularization. Conversely, evangelization rate showed OR = 1.024, indicating that for each 1% increase in evangelization, the odds of Christian growth rise by 2.4%. Thus, societies with an established Christian foundation exhibit greater potential for continued growth.

4.7 Conclusion

This study empirically examined the determinants of Christian growth across 180 countries. The analyses revealed that demographic, political–social, and cultural–technological factors influence Christian expansion in distinct ways.

First, population growth consistently emerged as the strongest explanatory variable across all analytical stages. It remained significant in correlation, multiple regression, and logit analyses, indicating that societies with increasing populations are more likely to experience Christian growth. This reaffirms that demographic dynamics constitute the fundamental structural condition for religious expansion.

Second, among political and social factors, the GRI, SHI, and political stability exhibited differing effects. A noteworthy finding is that while government restrictions showed little effect in simple correlation, they exerted a significant positive effect in regression analysis. This implies that state control does not always suppress religion; under certain conditions, it may stimulate cohesion and resilience within religious communities. In contrast, social hostility consistently produced negative effects on Christian growth, and political stability generally had a positive influence, though with opposite directions in Muslim- and Christian-majority contexts. This underscores the contextual nature of political and social environments in shaping religious outcomes.

Third, economic and educational variables did not display a strong positive association with Christian growth, contrary to expectations. In Christian-majority societies, higher education levels were negatively related to church expansion, aligning with secularization theory that posits advanced education and economic prosperity as constraints on religious growth.

Fourth, urbanization and internet penetration were insignificant in the global sample but strongly negative in Christian-majority contexts. Notably, internet access remained a significant suppressor of Christian growth in the logit model, reaffirming that digitalization and globalization weaken traditional religious authority and promote individualized forms of faith.

Fifth, evangelization rate demonstrated a significant positive relationship with Christian growth only below a 4% threshold. Beyond that level, the effect disappeared, indicating the presence of a nonlinear “threshold effect.” A minimal Christian community is required for growth to occur, but once that base is established, further expansion depends more on social, political, and cultural conditions than on evangelization rate alone.

5. Discussion

5.1 The Suppressive and Reinforcing Effects of Governmental Religious Restrictions

This study has examined various factors influencing Christian growth rates; however, several critical questions now arise. First, why do some countries with severe governmental restrictions on religion experience Christian growth, while others see decline? For instance, among nations with a Government Restrictions Index (GRI) above 7, Christianity was found to be growing in Indonesia, Iran, Malaysia, the Maldives, Egypt, Turkmenistan, Algeria, Saudi Arabia, Tajikistan, Eritrea, and Singapore, whereas it was declining in China, Russia, Syria, Uzbekistan, Kazakhstan, Morocco, Brunei, and Turkey.

Several factors may account for these differences. Countries such as Russia, Kazakhstan, Uzbekistan, and Syria possess historical Christian populations, yet they have experienced declines due to demographic contraction, emigration, war, and secularization. In these cases, the decrease in Christian population appears to be linked more closely to socio-demographic conditions than to direct government restrictions. Conversely, in countries such as Saudi Arabia, the Maldives, and Iran—where Islam is officially the only recognized religion—underground and house churches have emerged and expanded through migrant laborers and expatriate communities. In particular, in Saudi Arabia many foreign workers maintain a missionary identity even within their daily labor, planting new churches and contributing to Christian growth.

Such phenomena are not unique to the modern era but have recurred throughout two millennia of church history. Even under similar circumstances of persecution and hardship, some churches declined while others grew stronger. The same dynamic can be observed at the individual level: some abandon their faith amid adversity, while others emerge with deeper conviction.

The core question, therefore, is this: why do some churches collapse under persecution while others thrive within it? This question extends beyond church-growth studies to a more fundamental inquiry into how faith communities can endure suffering and become “overcoming churches.” As Boyd-MacMillan (2019) argued, the church needs not only a “theology of growth” but also a “theology of decline.” Understanding why some churches perish under persecution is equally crucial. Ultimately, the theme of “persecution and faith” warrants independent research, offering vital theological and practical implications for how the contemporary church responds to adversity.

5.2 Secularizing Factors: Internet and Education

According to this study’s findings, internet penetration and education primarily function as secularizing forces, showing no direct positive relationship with Christian growth. This does not negate the value of internet-based or educational missions; rather, it highlights the need to reassess their missional effectiveness in the modern era. The Korean example is illustrative: early missionaries such as Underwood and Appenzeller devoted themselves to educational missions by founding Kyungshin School and Pai Chai Hakdang, respectively. Indeed, many early-20th-century missionaries established schools in mission fields, opening doors for the gospel through literacy programs and intellectual formation. Yet paradoxically, some local students who benefited from such education—including higher education—later drifted away from faith and embraced secularism. This raises a fundamental question about the proper scope of educational missions and whether they remain an indispensable strategy in 21st-century mission practice.

Meanwhile, internet missions have emerged as a distinctive mode of evangelism, especially in regions inaccessible to traditional missionaries. Online platforms such as social media and YouTube have become powerful tools for spreading the gospel. Nonetheless, the actual contribution of these digital ministries to evangelization and church planting remains uncertain. Ultimately, both education and the internet possess dual characteristics: they are among the most powerful missionary resources and, at the same time, the most potent agents of secularization. Consequently, missionaries in the field must grapple with a fundamental question—how far to permit and how to guide local engagement with education and digital media in a way that supports, rather than undermines, the growth of faith communities.

5.3 Evangelization Rate and Unreached People Groups

When Ralph Winter introduced the concept of Unreached People Groups (UPGs) in 1974, he proposed that communities with less than 2 percent Christians should be classified as unreached. Although widely adopted, this standard was based on experiential judgment rather than empirical evidence. Half a century later, given the dramatic social transformations of the modern world, revising this concept appears necessary. While Winter himself did not insist rigidly on the 2 percent threshold, the criterion has nonetheless served as a pivotal benchmark for global mission strategy. Its central premise is that communities with evangelization rates below 2 percent cannot sustain self-propagating growth and therefore require external missionary intervention.

This study could not directly verify that hypothesis, but it revealed an important insight: even in areas where the evangelization rate exceeds 2 percent, church growth does not always occur. Particularly in the 4–10 percent range, Christian growth tends to stagnate. Below roughly 4 percent, increases in churches and believers accelerate growth, but before reaching a mature or stable phase, political, social, cultural, and economic factors appear to exert stronger influence. Beyond that phase, decline may even set in. While evangelization rate—i.e., the proportion of Christians—still affects growth, in such cases expansion occurs mainly through natural population increase rather than conversion. The continued negative growth of churches in low-fertility Europe exemplifies this pattern.

For example, Kyrgyzstan’s evangelization rate is approximately 4.8 percent, yet its Christian population decreases by about 1 percent annually. According to this study’s dataset, Kyrgyzstan’s GRI is 6.5 (high), its SHI 5.2 (above the global mean 2.7), and its political-stability score –0.65 (low). As regression analyses confirmed, both government restriction and political instability significantly affect Christian growth. Thus, despite a moderate evangelization rate, the structural conditions in Kyrgyzstan likely impede continued church planting and evangelism. In such contexts, external missionary engagement may still be essential for revitalization, even where evangelization rates are relatively high.

Of course, considering the asymmetrical distribution of missionary resources, prioritizing regions with low evangelization rates remains valid. Yet a low evangelization rate does not automatically mean that local churches are incapable of self-propagation. In some cases, external missionaries may even hinder indigenous church development. Conversely, among peoples with high evangelization rates but stagnating growth due to political, social, cultural, or economic constraints, missionary involvement can be crucial—though it should take a differentiated form, focusing on partnership and targeted evangelistic support rather than conventional pioneer missions.

In conclusion, while the concept of Unreached People Groups retains its missiological importance, it represents an outdated framework that cannot be uncritically applied to contemporary mission contexts. Future strategies must move beyond a single indicator such as evangelization rate and instead adopt context-specific, multidimensional approaches that incorporate each people group’s political, social, and cultural realities.

6. Conclusion

This study examined the growth rate of Christianity across 180 countries and analyzed the correlations and influences of various factors. Although numerous theories and claims regarding Christian growth and the dissemination of the gospel have been proposed within ecclesiastical circles and missiology, empirical validation using actual data has been relatively scarce. In this regard, the present study is significant in that it provides an empirical assessment of hypotheses that have accumulated over time. Moreover, it underscores the necessity of formulating mission strategies based on precise data rather than solely relying on experiential testimonies in missional practice.

Nine factors affecting the growth rate of Christianity were identified in this study, collectively explaining approximately 33% of the variance. This level of explanatory power is considered meaningful within the context of social science research. Nonetheless, it is crucial to acknowledge that the findings of this study do not constitute absolute truths. While the results can offer guidance and reference for mission strategy development, the ultimate outcome of mission endeavors remains dependent on God’s sovereignty and providence. Historically, the forebears of the faith advanced the kingdom of God by overcoming seemingly insurmountable challenges through faith—circumstances that statistics and empirical data alone cannot account for.

As the adage goes, “Statistics do not lie.” While data reflect reality as it is, God transcends these measurements and operates beyond human limitations. The remaining 67% of variance unexplained in this study may, in fact, represent the domain in which reliance on the Lord is paramount.

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