Use Cases Inventory

The OMOP GIS Vocabulary Package and its associated CDM extensions are developed iteratively in response to real-world research needs. This section inventories active and proposed use cases that drive the evolution of the GIS toolchain, including vocabulary enrichment, CDM schema extensions, analytical methods, and infrastructure improvements.

Each use case represents a specific research question, population health initiative, or analytical workflow that requires geospatial, environmental, or sociodemographic data integration within the OMOP framework.

7.1. Role of Use Cases in Toolchain Development

Use cases serve multiple functions within the GIS Working Group ecosystem:

7.1.1. Vocabulary Development

Use cases identify: - Missing concepts not currently represented in GIS vocabularies - Mapping gaps where source data lacks standardized OMOP equivalents - Hierarchical needs for aggregating or disaggregating spatial or environmental variables - Synonym requirements to improve discoverability of domain-specific terminology

Example: A childhood asthma study requiring fine particulate matter (PM2.5) exposure data at the Census tract level identified the need for granular air quality concepts and temporal aggregation indicators.

7.1.2. CDM Extension Priorities

Use cases inform: - Auxiliary table design for specialized analytical needs (e.g., time-series exposure modeling) - Field additions to external_exposure or related tables - Index and performance optimizations for large-scale spatial queries - Data linkage patterns between OMOP clinical data and external geospatial sources

Example: A life-course epidemiology study tracking residential mobility and environmental exposures over decades motivated the development of temporal location history extensions.

7.1.3. Analytical Method Development

Use cases drive: - HADES package enhancements for spatial statistics and environmental epidemiology - Custom R/Python libraries for geospatial data processing and visualization - Federated analysis protocols for privacy-preserving spatial analyses across networks - Validation frameworks for assessing exposure measurement quality

Example: A multi-site study of socioeconomic determinants of health outcomes required development of federated spatial regression methods compatible with OHDSI network study protocols.

7.2. Use Case Inventory

The following table inventories current and proposed use cases, categorized by research domain and development status.

Use Case ID Title Domain Status CDM Impact Vocabulary Impact Analysis Impact
UC-001 Childhood Asthma and Air Quality Environmental Epidemiology Active MVP 1 validation PM2.5, O3 concepts Spatial regression
UC-002 Social Vulnerability and COVID-19 Outcomes Sociodemographic Epidemiology Active MVP 1 validation SVI indices Multilevel modeling
UC-003 Built Environment and Physical Activity Behavioral Epidemiology Proposed Auxiliary tables needed Walkability, green space Network analysis
UC-004 Environmental Justice and Cancer Disparities Environmental + Social Epidemiology Proposed MVP 2 requirements EJI, SEDH integration Co-exposure modeling
UC-005 Residential History and Cardiovascular Disease Life-Course Epidemiology Proposed Location history extension Historical exposure reconstruction Survival analysis
UC-006 Noise Pollution and Mental Health Environmental Epidemiology Proposed Sound level concepts WHO noise indicators Time-series analysis
UC-007 Food Desert Mapping and Diabetes Sociodemographic Epidemiology Proposed Food access metrics USDA Food Atlas Spatial clustering
UC-008 Climate Change and Heat-Related Illness Climate Epidemiology Proposed Temperature exposure data Heat index, extreme weather Extreme value analysis

Note: This inventory is maintained collaboratively through the GIS Working Group GitHub repository. Community members are encouraged to propose new use cases via GitHub issues using the “Use Case Proposal” template.

7.3. Use Case Contributions to the Toolchain

Each use case contributes to one or more components of the GIS toolchain:

7.3.1. Vocabulary Enrichment

UC-001 (Childhood Asthma and Air Quality) contributed: - Standardized concepts for EPA air quality indices - Temporal aggregation categories (daily, seasonal, annual averages) - Mappings from EPA AirNow data to OMOP Exposome vocabulary - Hierarchical relationships for pollutant subcategories

7.3.2. CDM Schema Validation

UC-002 (Social Vulnerability and COVID-19) validated: - external_exposure table design for SVI index integration - Linkage patterns between Census tract identifiers and OMOP locations - Support for multi-component indices (SVI themes and overall ranking) - Temporal alignment of exposure periods with infection episodes

7.3.3. Analytical Infrastructure

UC-004 (Environmental Justice and Cancer Disparities) proposes: - HADES extensions for environmental justice metrics - Co-exposure network construction algorithms - Federated analysis protocols for sensitive geographic data - Visualization tools for spatial disparity assessment

7.4. Use Case-Driven MVP Roadmap

Future OMOP CDM MVPs will be explicitly tied to validated use case requirements:

MVP 2: Time-Series Exposure Modeling

Driven by: UC-005 (Residential History and CVD), UC-006 (Noise and Mental Health) Requirements: - Temporal sequence representation for repeated exposures - Support for moving window aggregations (e.g., 5-year average prior to diagnosis) - Integration with OMOP observation_period for longitudinal cohorts

MVP 3: Multi-Level Spatial Aggregation

Driven by: UC-007 (Food Deserts and Diabetes), UC-008 (Climate and Heat Illness) Requirements: - Hierarchical location relationships (tract → county → state) - Spatial aggregation functions (e.g., population-weighted averages) - Support for irregular geographic boundaries (school districts, hospital service areas)

MVP 4: Co-Exposure Network Modeling

Driven by: UC-004 (Environmental Justice and Cancer) Requirements: - Multi-exposure correlation structures - Joint distribution modeling for concurrent environmental and social factors - Network-based visualization and analysis tools

7.5. Emerging Research Domains

The GIS extension enables OMOP adoption in research domains that have historically lacked standardized observational data frameworks:

7.5.1. Environmental Epidemiology

Focus: Quantifying health impacts of air, water, soil, and noise pollution Key Challenges: - Spatiotemporal exposure assessment - Measurement error and uncertainty quantification - Integration of sensor data and modeled exposures - Multi-scale analysis (individual, neighborhood, regional)

Use Cases: UC-001, UC-004, UC-006, UC-008

7.5.2. Sociodemographic Epidemiology

Focus: Understanding how social determinants influence health outcomes Key Challenges: - Multilevel modeling of individual and area-level factors - Addressing structural confounding and selection bias - Privacy protection for sensitive geographic information - Intersectionality and interaction effects

Use Cases: UC-002, UC-007

7.5.3. Spatial Epidemiology

Focus: Analyzing geographic patterns and spatial clustering of health events Key Challenges: - Spatial autocorrelation and dependency - Boundary effects and modifiable areal unit problem (MAUP) - Visualization of spatial patterns while protecting privacy - Federated analysis across geographically distributed networks

Use Cases: UC-003, UC-004, UC-007

7.5.4. Life-Course Epidemiology

Focus: Examining cumulative and time-varying exposures across the lifespan Key Challenges: - Residential mobility tracking - Historical exposure reconstruction - Critical period and sensitive window identification - Intergenerational exposure effects

Use Cases: UC-005

7.6. Contributing Use Cases

The GIS Working Group welcomes use case contributions from researchers, public health practitioners, and data scientists working with OMOP CDM implementations.

7.6.1. Use Case Proposal Process

  1. Submit a GitHub Issue using the “Use Case Proposal” template at github.com/OHDSI/GIS/issues
  2. Describe the research question and target population
  3. Identify data requirements (geospatial datasets, exposure variables, temporal granularity)
  4. Specify analytical needs (statistical methods, visualization, federated analysis)
  5. Outline expected impact on vocabulary, CDM schema, or analytical tools

7.6.2. Use Case Review Criteria

Proposed use cases are evaluated based on: - Scientific rigor: Clear hypothesis and study design - Generalizability: Applicability beyond a single institution or dataset - Technical feasibility: Availability of required geospatial data sources - Community benefit: Contribution to shared toolchain components - Alignment with OHDSI principles: Open science, reproducibility, collaboration

7.6.3. Use Case Lifecycle

  1. Proposed: Initial submission and community review
  2. Active: Actively being used to drive development
  3. Validated: Successfully implemented and results published
  4. Reference: Serves as exemplar for similar future use cases

7.7. Use Case Resources

Each validated use case should include: - Study protocol describing research question and methods - Data sources with access information and licensing requirements - ETL scripts for integrating geospatial data with OMOP CDM - Analysis code (R/Python) demonstrating analytical workflows - Documentation including data dictionaries and validation results - Publications or reports disseminating findings

These resources are maintained in the GIS Working Group repository and linked from individual use case issues.

7.8. Future Directions

The use case inventory will continue to evolve as: - New research domains emerge (e.g., planetary health, urban health informatics) - Data sources expand (e.g., satellite imagery, mobile sensor networks, social media) - Analytical methods advance (e.g., causal inference for spatial exposures, machine learning for exposure prediction) - Policy needs shift (e.g., climate adaptation, health equity monitoring)

The GIS Working Group is committed to maintaining this inventory as a living document that reflects the dynamic landscape of geospatially-informed health research and ensures that the OMOP GIS extension remains responsive to community needs.