July 28, 2025

Summer Sublet Swarms: Transient Housing Patterns in College Towns

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The Geography of Student Housing Mobility

College towns during summer months experience unique housing patterns as students sublet apartments, seek short-term accommodations, and navigate the transition between academic years. This analysis examines census tracts in four major university towns—Gainesville (University of Florida), Ann Arbor (University of Michigan), Boulder (University of Colorado), and Austin (University of Texas)—to identify areas with high concentrations of within-county mobility that may indicate summer sublet ecosystems.

Using a novel “sublet swarm index” that combines residential mobility rates with college-age population density, the study reveals systematic patterns in how university proximity shapes short-term housing markets.

The Proximity Gradient: How Distance from Campus Shapes Mobility

The analysis reveals a clear proximity gradient in residential mobility patterns across all four college towns:

Table 1: Table 2: Residential Mobility Patterns by Distance from University Campuses
Campus ProximityTractsMean Within-County MovesMean College-Age RateStrong HotspotsModerate Hotspots
Very Close (≤3km)4421.7%37.4%2211
Close (3-6km)7612.4%7.7%49
Near (6-12km)11911.2%5.9%015
Far (>12km)2898.6%4.3%00

Very Close Areas (≤3km from campus) show dramatically higher mobility rates at 21.7% compared to distant areas at 8.6%. This represents a 2.5x difference in residential turnover, suggesting that proximity to campus creates intense short-term housing demand.

The Campus Housing Market Dynamic

The proximity gradient reveals distinct housing market zones:

Campus Core (≤3km): Areas within walking/biking distance of campus experience the highest mobility as students prioritize convenience and are willing to accept short-term, potentially suboptimal housing arrangements.

Transit Zone (3-6km): Moderate mobility areas where students balance cost, quality, and commute time, often serving as overflow areas when campus-adjacent housing fills up.

Commuter Belt (6-12km): Lower mobility areas that primarily serve graduate students, staff, and undergraduates with cars who prioritize housing quality over proximity.

Metropolitan Integration (>12km): Areas that function more like typical residential neighborhoods with minimal student influence.

University-Specific Patterns: Four Models of Student Housing Geography

Each university town displays distinct patterns reflecting different campus geographies, housing policies, and student cultures:

Boulder: Concentrated Student Zone Model

  • Enrollment: 35,000 students
  • Pattern: High spatial concentration of student housing
  • Mobility: Moderate average (10.7%) but high maximum (44.6%)
  • Geography: Compact campus creates tight clustering of student neighborhoods

Gainesville: Medium-Intensity Diffusion

  • Enrollment: 52,000 students
  • Pattern: Moderate dispersion across multiple neighborhoods
  • Mobility: Balanced average (10.6%) with moderate peaks (30.3%)
  • Geography: Larger campus and town size allows for more distributed student housing

Ann Arbor: Classic College Town

  • Enrollment: 46,000 students
  • Pattern: Traditional college town with mixed residential integration
  • Mobility: Steady baseline (9.8%) with significant peaks (43.5%)
  • Geography: Historic town structure creates pockets of intense student activity

Austin: Metropolitan Integration

  • Enrollment: 51,000 students
  • Pattern: University district within larger metropolitan area
  • Mobility: Moderate average (11.3%) but highest peaks (62.6%)
  • Geography: Major metropolitan area dilutes student concentration but creates extreme hotspots

The Sublet Swarm Index: Measuring Transient Housing Intensity

The relationship between college-age population and residential mobility reveals systematic patterns across all four university towns

Figure 1: The relationship between college-age population and residential mobility reveals systematic patterns across all four university towns

The scatter plot analysis reveals positive correlations between college-age population rates and within-county mobility in all four towns, with correlations ranging from moderate to strong. This validates the underlying hypothesis that areas with high concentrations of college-age residents experience elevated short-term housing turnover.

Boulder and Austin show the clearest linear relationships, suggesting systematic sorting of students into specific neighborhoods based on proximity and housing characteristics.

Ann Arbor and Gainesville display more scattered patterns, indicating greater integration of student and non-student populations or more diverse student housing preferences.

Distribution of Sublet Activity: Hotspots and Cold Zones

Distribution of sublet swarm indices shows different intensities of transient housing patterns across university towns

Figure 2: Distribution of sublet swarm indices shows different intensities of transient housing patterns across university towns

The sublet swarm index distribution reveals distinct patterns of housing mobility concentration:

Strong Hotspots (red): Areas with both high mobility and high college-age population that are close to campus, representing the core of summer sublet activity.

Moderate Hotspots (orange): Areas with elevated mobility or college-age population but not both, or areas farther from campus with some student presence.

Weak Signals (yellow): Areas with minor indicators of student housing activity.

No Pattern (gray): Areas that function as typical residential neighborhoods with minimal student influence.

The distribution patterns show that Boulder and Gainesville have more pronounced peaks of extreme activity, while Ann Arbor and Austin show more gradual transitions between zones.

Extreme Hotspots: The Geography of Peak Sublet Activity

The most intense sublet activity occurs in census tracts that combine:

  1. Proximity to Campus: Most hotspots are within 2-3km of university centers
  2. High Mobility: Within-county move rates of 20-40% or higher
  3. Student Concentration: College-age population rates of 15-30%

These areas likely represent the core student neighborhoods where summer subletting, semester-to-semester moves, and short-term housing arrangements are most common.

Spatial Patterns: Campus-Centered Housing Markets

Spatial distribution of sublet swarm patterns shows campus-centered housing markets with distinct geographic signatures

Figure 3: Spatial distribution of sublet swarm patterns shows campus-centered housing markets with distinct geographic signatures

The spatial maps reveal how university campuses function as gravity centers for transient housing markets:

Gainesville: Concentrated activity immediately adjacent to the University of Florida campus with rapid decay with distance.

Ann Arbor: Multiple nodes of activity reflecting both the central campus and satellite university facilities.

Boulder: Linear patterns following major transportation corridors connecting student neighborhoods to campus.

Austin: Sector-based patterns reflecting the university district within the broader metropolitan geography.

Policy and Planning Implications

The systematic patterns revealed in this analysis have important implications for urban planning and housing policy in university towns:

Housing Supply and Regulation

Short-Term Rental Policies: The identified hotspots represent areas where short-term rental regulations, subletting policies, and seasonal housing provisions need careful attention.

Zoning Considerations: Areas with high sublet indices may benefit from flexible zoning that accommodates transient housing needs while protecting neighborhood character.

Student Housing Development: The proximity gradient suggests optimal locations for purpose-built student housing that could reduce pressure on existing residential areas.

Transportation and Infrastructure

Transit Planning: High-mobility areas near campus require robust public transportation to reduce parking pressure and accommodate frequent resident turnover.

Infrastructure Resilience: Areas with high residential churn may need different approaches to utility management, waste collection, and municipal services.

Neighborhood Stability: Understanding mobility patterns helps predict which areas need additional community-building investments.

Economic Development

Local Business Adaptation: Businesses in high-mobility areas should consider seasonal patterns and transient customer bases in their planning.

Property Management: Landlords in identified hotspots face different challenges and opportunities than those in stable residential areas.

Tax and Revenue Planning: Municipal revenue planning should account for the different fiscal impacts of transient vs. permanent residents.

Methodological Innovation: From Block Groups to Tracts

This analysis required significant methodological adaptation when residential mobility data proved unavailable at the block-group level:

Data Availability Challenges

Geographic Resolution: ACS residential mobility variables (B07003 series) are only available at census tract level or higher, not block groups, requiring adjustment of the analytical framework.

Variable Validation: Systematic exploration of ACS variable catalogs revealed that many demographic analyses must work within geographic constraints imposed by data collection methods.

Spatial Scale Trade-offs: Using tracts instead of block groups reduces spatial precision but enables access to critical mobility variables not available at finer geographic scales.

Index Construction Innovation

Composite Methodology: The sublet swarm index combines standardized within-county mobility rates with college-age population rates, providing a more robust measure than either indicator alone.

Town-Specific Normalization: Z-score standardization within each university town accounts for different baseline conditions while preserving comparative analysis across cities.

Distance Integration: Including campus proximity in hotspot classification ensures that mobility patterns are interpreted within geographic context of university influence.

Limitations and Future Research Directions

Data and Temporal Constraints

Annual Aggregation: ACS data represents annual averages and cannot capture the seasonal patterns (summer vs. academic year) that drive sublet markets.

Mobility Definition: “Within-county moves” includes all short-distance relocations, not just student-driven subletting, requiring interpretation within university town context.

Age Categories: Census age categories don’t perfectly align with undergraduate student populations, particularly for non-traditional students.

Geographic and Methodological Limitations

Campus Location Precision: Using single-point campus locations may not accurately represent large university complexes with multiple student activity centers.

Tract-Level Aggregation: Census tracts may include both high-student and non-student areas, potentially masking finer-scale patterns.

Cross-Sectional Analysis: Single time period analysis cannot capture trends or changes in student housing patterns over time.

Future Research Opportunities

Longitudinal Analysis: Multi-year analysis could reveal how student housing patterns evolve with enrollment changes, housing development, and policy modifications.

Seasonal Decomposition: Integrating American Community Survey data with higher-frequency data sources could better capture summer vs. academic year patterns.

Comparative Expansion: Including additional university towns with different characteristics (public vs. private, urban vs. rural, different sizes) could test generalizability.

Causal Inference: Natural experiments around new dormitory construction, zoning changes, or transportation improvements could help establish causal relationships.

Conclusion: Mapping the Invisible Geography of Student Housing

This analysis reveals that summer sublet markets in university towns follow systematic geographic patterns that can be measured and mapped using census data. Rather than random distributions, student housing mobility concentrates in predictable zones defined by campus proximity, creating distinct sublet swarms that represent the hidden geography of transient student housing.

Key Findings

Proximity Gradient: Within-county mobility rates decline systematically with distance from campus, from 21.7% within 3km to 8.6% beyond 12km.

University-Specific Patterns: Each university town displays distinct spatial signatures reflecting campus geography, enrollment size, and metropolitan context.

Composite Index Validity: The sublet swarm index successfully identifies hotspots that combine high mobility with high college-age population and campus proximity.

Policy Relevance: Identified patterns provide actionable information for housing policy, zoning decisions, and infrastructure planning in university communities.

Broader Implications

Understanding student housing mobility patterns helps university towns balance competing needs:

  • Student Housing Access: Ensuring adequate, affordable housing options within reasonable distance of campus
  • Neighborhood Stability: Protecting residential character while accommodating transient populations
  • Economic Vitality: Supporting businesses that serve both student and permanent populations
  • Infrastructure Efficiency: Planning services that work for both stable and mobile residents

The methodology developed here provides a replicable framework for analyzing student housing geography in any university town, contributing to evidence-based planning in communities where universities are major economic and social forces.

By making visible the usually invisible patterns of student housing mobility, this analysis helps university towns better understand and plan for the complex housing ecosystems that emerge around major educational institutions.


Technical Notes

Data Sources: 2018-2022 American Community Survey 5-year estimates (Tables B07003: Geographical Mobility, B01001: Age and Sex)
Geographic Coverage: Census tracts in Alachua County FL, Washtenaw County MI, Boulder County CO, Travis County TX
University Campuses: University of Florida, University of Michigan, University of Colorado Boulder, University of Texas Austin
Analytical Methods: Z-score standardization, distance calculation, composite index construction
Population Thresholds: 100+ residents per tract for inclusion in analysis
Distance Calculation: Euclidean distance from tract centroids to campus coordinates

© Dmitry Shkolnik 2025

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