01 · The Gospel Desert Concept
Origin and rationale.
The Gospel Desert Index (GDI) adapts the food desert concept from urban planning to the domain of evangelical witness. A food desert is an area where residents lack reasonable access to nutritious food due to structural factors — not personal failure. The GDI applies the same logic: a Gospel Desert is a Census tract where the structural conditions that typically enable sustained evangelical witness are absent or severely degraded.
This is a deliberately structural claim, not a spiritual one. The index does not purport to measure where the Spirit is at work. It measures whether the external, observable infrastructure of Gospel presence — accessible churches, institutional anchors, neighborhood vitality — exists at a level that makes incarnational ministry tractable.
The GDI identifies where incarnational presence is most structurally needed, not where God is absent. A tract in the Desert tier may have faithful believers, house churches, and Spirit-driven fruit invisible to any dataset. The index is a tool for resource allocation, not a map of divine sovereignty.
Theological assumptions.
The GDI rests on four explicit theological commitments that both motivate and constrain what the index claims to measure.
Ordinary Means
Reformed ecclesiology holds that God ordinarily works through means: the Word preached, the sacraments administered, the community gathered. The structural absence of a faithful, accessible church is therefore missiologically significant — not because God cannot work without one, but because He has ordained that He ordinarily does work through one.
Incarnational Presence
Harvie Conn's incarnational urban missiology holds that Gospel access requires not merely the existence of a church within a geographic radius, but the presence of believers embedded in the social fabric of a community — who know its people, share its material conditions, and bear witness from within. Geographic proximity is necessary but insufficient.
Observable Fruit
Jonathan Edwards argued that the chief evidence of genuine conversion is consistent, habitual practice shaped by holy love. What begins as inward regeneration eventually presses outward into how a person serves their neighbor. These practices, repeated across many lives, aggregate into community-level patterns. The GDI measures structural preconditions; the Gospel Impact Metric (GIM) measures fruit. These are distinct instruments that must be used together.
Antifragility
Following Nassim Taleb, THS recognizes that Gospel Desert conditions are not simply barriers to ministry — they are the conditions under which genuine, resilient faith communities are forged. A church planted in a Desert-tier tract that survives and grows over a decade has demonstrated a robustness that a church planted in favorable conditions cannot.
02 · Data Architecture
Three layers. One join key.
The GDI is constructed from three independent data layers joined at the Census tract FIPS key — an 11-digit identifier combining state (2), county (3), and tract (6) codes. The United States contains approximately 84,000 Census tracts, each designed to capture socially coherent neighborhood units of 1,200–8,000 residents.
| Layer | Source | Cycle | Primary Output |
|---|---|---|---|
| Church Location | OpenStreetMap + IRS 990 BMF | Annual | church_count, nearest_church_m |
| Structural Signals | Census LEHD LODES8 | Annual (~2yr lag) | activation_ratio, pedestrian_index |
| Demographic Context | ACS 5-Year Estimates | Annual (5yr avg) | poverty_rate, vacancy_rate |
Layer 1: Church location data.
OpenStreetMap
OSM is the primary source for point locations of places of worship. At national scale, data is pulled from Geofabrik state-level PBF extracts rather than live API queries. OSM records are tagged amenity=place_of_worship and include name, denomination, and religion fields. Coverage is strong in urban areas; denomination metadata is inconsistent nationally.
IRS 990 Business Master File (NTEE X-Codes)
The IRS publishes the complete BMF of 501(c)(3) organizations with NTEE classification codes. Codes X00–X99 designate religion-related organizations. Key codes: X20 (Protestant), X21 (Catholic), X30 (Islam). Code X80 (religious media/publishing) is excluded from church counts.
Output Fields per Tract
church_count— Total church-like organizations in tractnearest_church_m— Distance from tract centroid to nearest churchchurch_density_per_sqmi— Church density normalized to land areachurch_denominations— Count of unique denominations present
Layer 2: LODES structural signals.
The Census Bureau's LEHD Origin-Destination Employment Statistics (LODES) dataset links employer payroll records with Census demographics to produce block-level counts of jobs by industry, wage, and worker characteristics. LODES covers formal employment only — informal economy activity, volunteer presence, and the kind of relational foot traffic Jane Jacobs identified as the animating fabric of neighborhood life are not captured.
Workplace Area Characteristics (WAC)
WAC files count jobs located in each Census block by industry sector. The derived field wac_pedestrian_index = retail + food service + healthcare jobs — the three sectors most reliably associated with daytime pedestrian traffic generation.
Origin-Destination Activation Ratio
The field od_activation_ratio = (workers arriving to work in tract + 1) / (workers leaving tract to work + 1). A ratio above 1.0 indicates a tract that receives workers — commercial corridors, institutional anchors. A ratio below 1.0 indicates a residential exporter whose sidewalks are empty during the day.
Layer 3: ACS demographic context.
ACS 5-year estimates provide tract-level demographic and economic context via the Census API. The 5-year averaging window substantially reduces sampling error at the tract level, making estimates statistically reliable without the margin-of-error concerns that affect block-group-level data.
- B01003 — Total population
- B17001 — Population below poverty line →
poverty_rate - B25002 — Housing vacancy →
vacancy_rate - B23025 — Labor force / unemployed →
unemployment_rate - B03002 — Race/ethnicity breakdown
03 · Scoring Methodology
Four domains. One composite.
All domain scores are computed using percentile ranking within the full national tract dataset. The GDI measures relative severity — a tract scoring 75 is more structurally desert-like than 75% of all U.S. tracts, not an absolute threshold.
The GDI is the sum of four domain scores, each ranging 0–25. Higher scores indicate greater structural absence of the conditions that enable Gospel access.
Domain A
Church Access
Density + proximity + denominational diversity. Highest-weighted domain: the most direct structural precondition for Gospel access.
church_density · nearest_church_m · denominations
Domain B
Structural Absence
Daytime isolation + institutional thinness. Derived from LODES activation ratio and job sector flags.
od_activation_ratio · gd_composite_signal
Domain C
Social Fragility
Poverty + vacancy + unemployment. Conditions that historically correlate with barriers to church participation.
poverty_rate · vacancy_rate · unemployment_rate
Domain D
Population Reach
Urgency multiplier. A Desert-tier tract with 8,000 residents represents greater aggregate need than one with 400.
pop_total percentile rank
The five-tier classification.
| Tier | GDI | Description |
|---|---|---|
| Watered | 0–25 |
Multiple accessible churches, active community presence, low structural barriers |
| Sparse | 25–45 |
Some church access but meaningful gaps in coverage or accessibility |
| Dry | 45–60 |
Structural barriers present; church access declining or thin |
| Arid | 60–75 |
Significant absence of Gospel presence and supporting structures |
| Desert | 75–100 |
Critical priority for incarnational church planting |
04 · Underlying Assumptions
What the index assumes.
Every index embeds assumptions. Identifying them explicitly is not a concession to methodological weakness — it is a precondition for responsible use.
Church proximity is a meaningful proxy for Gospel access
The GDI assumes that geographic distance between a resident and the nearest evangelical church is a meaningful indicator of access. Cultural, linguistic, and economic distance can render physically proximate churches functionally inaccessible. The index treats physical proximity as necessary but not sufficient.
Formal employment data reflects meaningful economic presence
LODES measures formal, payroll-reported employment. It does not capture informal economy activity, gig work, or the relational foot traffic that Jane Jacobs identified as the animating fabric of neighborhood life. A Desert-tier tract in a dense urban environment may have vibrant informal social networks invisible to LODES.
ACS estimates reflect stable tract conditions
ACS 5-year estimates smooth out year-to-year volatility, improving reliability but reducing sensitivity to rapid change. A rapidly gentrifying tract may carry outdated figures. The GDI is a baseline condition measure, not a real-time status indicator.
The survivorship bias problem
Any dataset of existing churches captures only churches that have survived. Failed church plants and dissolved congregations are absent from OSM and IRS data by definition. The church access domain may undercount the structural difficulty of a tract because prior failure is invisible in the data. THS maintains a failed church dataset as a planned survivorship-bias correction to Domain A.
The Lindy Effect on temporal validity
Following Taleb's Lindy Effect, structural conditions that have persisted for decades are likely to persist for decades more. A Gospel Desert that has been a Gospel Desert since 1970 is not likely to self-correct without deliberate, sustained incarnational investment. This gives the GDI long-horizon validity as a diagnostic while cautioning against treating any single build as definitive.
05 · Denominational Application
From the national map to the pastoral report.
The GDI is designed to serve a three-stage church planting site selection workflow. Each stage corresponds to a different geographic scale and a different product output.
Metro Prioritization
Network leadership identifies which cities to enter next. Input: gospel_desert_by_metro.csv — tracts aggregated to CBSA. Output: ranked list of metros by Desert-tier tract count and total population exposed. The presentation layer for General Assembly or network planting summit conversations.
Neighborhood Shortlisting
Regional directors narrow from metro-level to 8–12 candidate tracts. Input: the GospelGraph map filtered to the target metro, showing Desert and Arid-tier tracts with domain score breakdowns. This is where the GDI replaces gut instinct with a defensible field of candidates.
Site Assessment
Church planting teams assess specific candidates in depth. Input: GIM Intake Wizard at gospelgraph.com. Output: Gospel Impact Metric baseline score for the tract. The GDI narrows the field; the GIM assesses the ground. Both are required before a planting commitment.
The GDI answers Stages 1 and 2. The GIM answers Stage 3. A denomination should not make a planting commitment based on GDI scores alone. The GDI identifies where a site visit and GIM intake are warranted — not where a church should be planted.
The GDI × GIM matrix.
The most analytically powerful read is the 2×2 matrix of GDI tier versus GIM score. Comparing them — not blending them — is where the most useful pastoral insight lives.
| High GIM — Fruit Present | Low GIM — Fruit Absent | |
|---|---|---|
| Low GDI — Watered | Healthy — sustain and multiply existing presence | Concern — structural access exists but fruit is absent |
| High GDI — Desert | Remarkable — faithful witness under structural adversity | Critical — highest priority for new planting investment |
06 · Honest Limits
What you can — and cannot —
reasonably conclude.
The GDI produces real and useful information. It also has real and important limits. What follows is the plain-language version of both.
Numbers can tell you a tract has a 38% poverty rate and no nearby evangelical churches. They cannot tell you about the widow in Building C who leads a Bible study for twelve of her neighbors. Both are real. The data serves the pastor. It does not replace him.
"We have this treasure in jars of clay, to show that the surpassing power belongs to God and not to us."2 Corinthians 4:7
The Gospel Desert Index is a jar of clay. Use it to see more clearly.
Let it push you toward the street, not away from it.
And never let the score replace the face of the neighbor you are called to love.