Building a Thriving Church Health Ecosystem Part 11: Theological Conservatism and Church Health

Theological Conservatism and Church Health: What the Data Really Says

Theological Conservatism and Church Health: What the Data Really Says

Dr Ian Duncum

Church Health Ecosystem Series | Post 11

This post, we tackle one of the most debated questions in congregational research: Does theological conservatism make churches healthier?

The answer, as with most things in church life, is “it depends”—but the data offers some clear patterns worth understanding for leaders across the theological spectrum.

What Do We Mean by “Theological Conservatism”?

Before diving into statistics, it’s important to define terms. In empirical research, “theological conservatism” typically refers to:

• High views of biblical authority

• Traditional Christology (e.g., belief in the physical resurrection, exclusivity of salvation through Christ)

• Clear behavioural expectations for members

• Self-identification as evangelical, confessional, or fundamentalist [journals.sagepub][ray.yorksj.ac][the-way]

By contrast, “theological liberalism” or “mainline” traditions tend to emphasise:

• Symbolic or contextual biblical interpretation

• Inclusivity and openness to diverse beliefs

• Social-justice engagement

• Adaptation to cultural change

These are broad strokes—many congregations and denominations sit somewhere in between, may take elements from both lists (eg a theologically conservative church with a justice engagement in their local community), and there is significant internal diversity within denominations (e.g., evangelical vs. liberal Anglican dioceses in Australia).[ray.yorksj.ac]

The Growth Question: Do Conservative Churches Grow More?

The most robust and replicated finding across 50+ years of research is that theologically conservative denominations and congregations have grown numerically, while liberal/mainline ones have declined.

International Evidence

• Dean Kelley’s 1972 landmark study, Why Conservative Churches Are Growing, analysed denominational statistics and found that strict, conservative groups (e.g., Assemblies of God, Southern Baptists) grew at or above population rates, while mainline liberal denominations (e.g., Episcopal, United Church of Christ, Presbyterian Church USA) declined.

• Hoge and Roozen’s multi-denominational analysis (1950–1978) confirmed that, controlling for socioeconomic and demographic factors, theological conservatism remained a significant predictor of growth in mainline Protestant congregations.[pewresearch]

• Canadian mainline study (Ontario, 2016): Surveying over 2,000 attenders and 29 clergy across 22 growing vs. declining mainline churches, researchers found that theological conservatism of both clergy and attenders predicted growth, while liberalism predicted decline.[journals.sagepub][the-way]

• Hartford Institute FACT 2025: Tracking over 7,000 US congregations, researchers reported that post-pandemic attendance growth occurred “mostly in evangelical or conservative Protestant churches,” while many liberal congregations continued to stagnate.

Australian Evidence

• NCLS Research (1991–2025): Across six national survey waves, evangelical and conservative Protestant streams (e.g., Baptist, Pentecostal, Anglican evangelical) have shown higher retention and growth rates than mainline liberal denominations (e.g., Uniting Church, Anglican broad-church/liberal).

• 2016–2021 data: Only 18% of Australian Protestant churches were growing (by 10% or more), while 69% were declining. Growth was concentrated in theologically conservative, outward-focused congregations with strong discipleship pathways.

• 2025 Church Pulse Check: Weekly attendance had recovered to 89% of 2001 levels, but growth remained uneven, with conservative evangelical and Pentecostal streams outperforming mainline denominations.

Statistical strength: These findings are supported by multivariate analyses controlling for age, income, education, and regional demographics. Theological conservatism typically emerges as a significant independent predictor of attendance growth, with moderate to strong effect sizes.[journals.sagepub][pewresearch]

Spiritual Vitality: A More Nuanced Picture

When “spiritual vitality” is measured by leaders’ self-assessment of whether their congregation is “spiritually vital and alive,” the results are more surprising.

Hartford Institute FACT 2020 Report

• 40% more congregations strongly agreed they were “spiritually vital and alive” in 2020 than in 2015.

• Most spiritually vital congregations shared these characteristics:

  • Openness to new people

  • Willingness to change

  • Thought-provoking worship

  • Emphasis on religious education (children and adults)

  • Integration of faith into daily life

  • Higher participation of younger people

• Crucially, the report noted “minor variances by faith tradition and denomination”, implying that both conservative and liberal congregations could score high on vitality when they exhibited these practices.

Counter-Narratives

• Diana Butler Bass, citing earlier Hartford data, claimed that liberal congregations sometimes display higher levels of self-reported spiritual vitality than conservative ones—a “counter-intuitive” finding relative to the growth narrative.

• However, this claim is not consistently replicated in later FACT reports, which emphasise common denominators of vitality across traditions rather than liberal–conservative splits.

Interpretation: Self-reported vitality may reflect subjective perceptions of aliveness (e.g., worship quality, community warmth, social-justice engagement) that are not tightly correlated with numerical growth or doctrinal strictness. Liberal congregations may feel spiritually vibrant even as attendance declines, while conservative congregations may feel spiritually dry despite growth.

Discipleship, Giving, and Other Vitality Indicators

Discipleship Behaviours

Research on individual spiritual practices shows a clearer conservative advantage.

• Lifeway Research (US, 2024–2026): Protestant churchgoers who participate in small-group Bible studies five or more times per month scored 74.1/100 on an eight-dimension discipleship index, compared to 60.4 for non-participants.

• The largest gaps were in “Sharing Christ” (69.7 vs. 41.1) and “Obeying God and denying self”, practices more commonly emphasised in conservative evangelical traditions.

• NCLS Australia: Prayer, Bible reading, and faith-sharing are more frequent among attenders in conservative evangelical and Pentecostal churches than in mainline liberal congregations.[ray.yorksj.ac]

Giving and Financial Vitality

• Science of Generosity Initiative (US): Religious conservatism positively predicts charitable giving, attendance, and pledging, even after controlling for income and education.

• NCLS Australia: Conservative evangelical and Pentecostal attenders give a higher percentage of income to their churches than mainline liberal attenders.

• Hartford Institute 2025: Financial stability improved post-pandemic, but “net growth occurred mostly in evangelical or conservative Protestant churches.”

Inclusion and Social Justice

• NCLS core qualities: Mainline churches often score higher on inclusion, diversity, and social-justice engagement, reflecting different theological priorities.[str]

• This suggests that different traditions prioritise different dimensions of health, and a composite view of vitality is necessary for fair comparison.

Theological Training for Clergy: A Missing Piece?

One underexplored factor in the conservatism–vitality link is theological training for clergy. Several studies suggest that how pastors are formed theologically and practically shapes both their congregations’ trajectory and their own resilience.

Key Findings

• Canadian mainline study (2016): Clergy in growing churches were more likely to have received training that emphasised biblical literacy, evangelism, and discipleship pathways, regardless of denominational label.[journals.sagepub][the-way]

• NCLS Australia (2020): Pastors who reported ongoing theological reflection, peer supervision, and practical ministry skills (e.g., preaching, pastoral care, vision-casting) led congregations with higher scores on multiple vitality dimensions.

• Hartford Institute (2023): Mainline clergy who participated in continuing theological education showed greater openness to change and innovation, which correlated with higher self-reported vitality—even in declining congregations.

Implications for Training Institutions

For seminaries and theological colleges, these findings suggest several priorities:

1. Integrate theory and practice: Clergy need both deep theological grounding and hands-on skills in preaching, discipleship, and organisational leadership.

2. Foster theological reflection: Ongoing formation (e.g., peer groups, supervision, retreats) helps pastors navigate change without losing their theological centre.

3. Equip for diverse contexts: Training should prepare clergy for both conservative and liberal congregational cultures, emphasising adaptability and contextual intelligence.[journals.sagepub][the-way]

4. Address burnout and resilience: Clergy wellbeing is a significant predictor of congregational health; training programmes should include mental-health and self-care components and, in line with other helping professions, pastoral supervision should be mandated.

For church leaders, investing in ongoing theological and practical development—not just initial ordination training—may be one of the highest-leverage strategies for sustaining vitality across the theological spectrum.

Methodological Caveats

Before drawing conclusions, it’s worth noting several limitations in the research:

1. Correlation ≠ Causation: Theological conservatism correlates with growth, but other factors (demographics, organisational practices, cultural context) also play significant roles. Nevertheless, Kaldor et al in Shaping a Future identify a church's internal factors as the most significant influence on vitality.

2. Measurement Bias: Self-reported vitality may be inflated in congregations that value subjective experience (often liberal) or deflated in those that emphasise sin and repentance (often conservative).

3. Denominational Heterogeneity: Not all “conservative” or “liberal” denominations are monolithic. For example, Anglican evangelical dioceses (e.g., Sydney) show growth, while liberal dioceses (e.g., Melbourne) show decline.[ray.yorksj.ac]

4. Australian Specifics: Higher secularisation (46% of young drop-outs cite “no religion”) and smaller sample sizes in NCLS surveys affect generalisability.

What This Means for Church Leaders

So, what should leaders take away from this data?

1. Theology Matters, But Practices Matter More

Conservative theology often correlates with growth because it is embedded in high-commitment practices (small groups, evangelism, discipleship). Liberal congregations that adopt similar practices—intentional faith formation, clear vision, welcoming community—can also achieve vitality.[the-way]

2. Avoid Conflating Numerical Growth with Spiritual Health

A growing church may be theologically shallow or consumer-oriented; a declining church may be deeply faithful in a secular context. Multiple dimensions of vitality (discipleship, inclusion, service, innovation) should be tracked, not just attendance.

3. Invest in Clergy Formation

As noted above, ongoing theological and practical training for pastors is a significant predictor of congregational health. Churches that support their leaders’ continued learning—through supervision, peer groups, and professional development—tend to be more resilient and adaptable.

4. Focus on Retention and Innovation (Especially in Australia)

With 72% of young Australians dropping out of church by their late 20s, young-adult retention, newcomer assimilation, and culturally relevant worship are critical for all traditions.

5. Use Multi-Dimensional Vitality Indices

Relying solely on attendance or self-reports gives an incomplete picture. Composite measures (e.g., NCLS’s nine core qualities, REVEAL’s Spiritual Vitality Index) offer more nuanced insights for diagnosis and planning.

A Quick Reference Table

Dimension of Vitality	Conservative Advantage?	Key Evidence
Numerical growth	Yes, strong	Kelley (1972), Hoge & Roozen (1978), Canadian mainline study (2016), NCLS Australia (1991–2025), Hartford FACT (2025) [journals.sagepub][the-way][pewresearch]
Attendance stability	Yes, moderate	NCLS 2016–2021: 70% of Protestant churches declining, growth concentrated in conservative streams
Discipleship behaviours (prayer, Bible, evangelism)	Yes, moderate to strong	Lifeway 2024–2026, NCLS Australia, Canadian study [ray.yorksj.ac]
Giving levels	Yes, moderate	Science of Generosity, NCLS, Hartford 2025
Self-reported spiritual aliveness	Mixed/nuanced	Hartford FACT 2020: common denominators across traditions; earlier claims of liberal advantage not consistently replicated
Inclusion, social justice, innovation	Liberal advantage in some studies	NCLS core qualities: mainline churches often score higher on inclusion and service, though this varies by congregation [str]

Final Thoughts

The statistical evidence supports a qualified version of the “conservative churches grow” thesis: across Australia, the US, and Canada, theologically conservative denominations and congregations consistently outperform liberal ones on numerical growth, attendance stability, discipleship behaviours, and giving. However, when “spiritual vitality” is measured by self-reported aliveness, openness to change, or social-engagement metrics, the advantage diminishes or disappears, with some liberal congregations scoring highly.

For leaders building a church health ecosystem, the takeaway is not to adopt conservatism for growth’s sake, but to embody the practices that sustain vitality in any tradition: clear vision, intentional discipleship, welcoming community, and faithful witness. As NCLS Research summarises, healthy churches strengthen relationships with God, with each other, and with the wider community—regardless of their position on the theological spectrum.[str]

And for those investing in theological training for clergy, the data suggest that integrating deep theological reflection with practical ministry skills—and supporting ongoing formation—may be one of the most impactful strategies for fostering long-term congregational health.

References (Selected)

1. NCLS Research. Church vitality: background. https://www.ncls.org.au/articles/church-vitality

2. Haskell, D. et al. (2016). Comparing the Traits of Growing and Declining Mainline Protestant Churches. Review of Religious Research.[journals.sagepub][the-way]

3. Hartford Institute for Religion Research. Faith Communities Today 2020 Report on Congregational Vitality. https://www.hartfordinternational.edu/news-events/news/faith-communities-today-issues-report-congregational-vitality

4. Kelley, D. M. (1972). Why Conservative Churches Are Growing. Harper & Row.

5. Village, A. (2016). Biblical conservatism and psychological type among Australian clergy. Journal of Empirical Theology.[ray.yorksj.ac]

6. Lifeway Research. (2024–2026). Small Groups and Discipleship Analysis. https://research.lifeway.com

7. Koyzis, D. T. (2012). Collapse or vitality: liberal versus conservative Christianity. First Things. https://firstthings.com/collapse-or-vitality-liberal-versus-conservative-christianity/

8. NCLS Research. (2021). Church Growth, Decline, Planting and Multiplication in Australia. https://exponential.org.au

9. Pew Research Center. Religious Landscape Study. https://www.pewresearch.org/religious-landscape-study/

10. Science of Generosity Initiative. Religious Giving. https://generosityresearch.nd.edu

(This post is part of the Church Health Ecosystem blog series, designed for denominational leaders, clergy, trainers, and researchers interested in evidence-based ministry and organisational health.)

© 2026 Ian Duncum. All rights reserved. No reproduction without written permission.

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Rev Dr Ian Duncum is a trained and accredited church consultant with over 20 years of experience with non-profit enterprises and churches across several denominations. This includes denominational leadership in church health, church planting, consultancy training, and adjunct lecturing & research in the tertiary education sector. An accredited minister with a track record of growing churches, Ian trains church consultants, facilitates training for ministers and leaders, and supervises pastors and other leaders. Ian can be contacted at ian@ianduncum.com.au.