How do we protect data privacy in CTPP tabulations?

Challenge

To support state and local transportation agencies, the Census Transportation Planning Products (CTPP) program produces highly detailed tabulations of American Community Survey (ACS) data, which must adhere to stringent requirements for disclosure avoidance. As demand for granular public data continues to grow alongside rising privacy risks, the U.S. Census Bureau needed an approach that would maintain data confidentiality while retaining analytical usefulness.

Solving this challenge is important not only for transportation planning but also for helping future federal, state, and local data programs share secure and actionable information. Enhanced disclosure avoidance methods can facilitate the release of more data, thereby providing increased support for informed decision-making.

Solution

Westat addressed this challenge by generating synthetic ACS microdata tailored for transportation planning and applying advanced disclosure avoidance techniques. Central to this effort is the model-assisted constrained hotdeck (MACH) methodology, which combines predictive modeling with constrained imputation to retain key statistical relationships and maintain respondent confidentiality. Our team developed and validated disclosure avoidance methods, built supporting statistical models, and implemented complex workflows to ensure both utility and privacy.

Westat also produced comprehensive documentation, conducted quality and consistency checks, and provided technical support for tabulations and variance estimation. Westat’s SDCPert software automates critical components of the MACH process, enhancing reproducibility and performance.

With expertise in disclosure avoidance, ACS data, statistics, and data science, Westat delivers integrated, secure, and high-quality solutions that few firms can match.

Results

The project delivers high-fidelity synthetic ACS microdata, enabling the Census Bureau to generate detailed tabulations for transportation planners without compromising confidentiality. State and local transportation departments can now access reliable information on commuting patterns, transit use, and roadway needs to support data-driven investment and policy decisions.

Beyond immediate improvements to the CTPP program, this work provides a model for how federal, state, or local agencies with large and complex datasets can responsibly release detailed data products. Ultimately, Westat’s solutions strengthen trust in government data programs and advance best practices in privacy-enhanced techniques.

Latest Report

Census Transportation Planning Products Data Synthesis Program Processing: Draft Methodology Report (PDF)