An article published in Social Indicators Research is the first to examine transportation insecurity alongside other forms of material hardship (i.e. food and housing insecurity, utility shutoffs). Findings show that transportation insecurity is among the most prevalent forms of hardship, that the demographic groups likely to experience it are also likely to experience other forms of hardship, that transportation insecurity and food insecurity are the hardships most likely to co-occur with other hardships, and that transportation insecurity is associated with physical and mental health at a similar magnitude as is food insecurity and having unmet medical needs.
Using a split-ballot design to validate an abbreviated categorical measurement scale: An illustration using the Transportation Security Index
In this methodological article published in Survey Practice, the developers of the Transportation Security Index use both content and statistical approaches to identify an abbreviated Transportation Security Index composed of 6 questions (TSI-6). The TSI-6 was then validated using nationally representative data that included a split ballot experiment. The validated TSI-6 successfully reproduces the original, validated TSI-16 but takes less time to complete and identifies fewer (3) categories of transportation insecurity.
A Driver in Health Outcomes: Developing Discrete Categories of Transportation Insecurity
A paper published in the American Journal of Epidemiology uses an inductive, mixed methods approach to identify, using the TSI-16, five categories of transportation insecurity (secure, marginal, low, moderate, high). Demonstrating the usefulness of these categories for research and screening, analyses of 2018 nationally representative data demonstrate that there exists different nonparametric associations between transportation insecurity and two distinct health outcomes. Whereas there was a threshold relationship between self-rated health and any level of insecurity, the risk of depressive symptoms showed a non-linear dose-response relationship with severity of transportation insecurity.
Transportation Insecurity in the United States: A Descriptive Portrait
An article published in Socius is the first to document the prevalence of transportation insecurity in the U.S. Findings show that in 2022, 1 in 4 people in the U.S. over the age of 25 experienced transportation insecurity; more than half (53%) of those living below the poverty line did. Beyond poverty, adults who do not own cars, live in urban areas, are younger, have less education, and are non-White experience the greatest transportation insecurity. Correlated analyses confirm these descriptive differences.
Validating the Sixteen-Item Transportation Security Index in a Nationally Representative Sample: A Confirmatory Factor Analysis
In a follow-up article to their 2018 Survey Practice practice article, in this Survey Practice article the developers of the Transportation Security Index draw upon nationally representative survey data and use confirmatory factor analysis to validate the 16-question Transportation Security Index. Results show that transportation insecurity is a unidimensional condition, experienced both materially and relationally.
Developing a New Measure of Transportation Insecurity: An Exploratory Factor analysis
A methodological article published in Survey Practice is where the developers of the Transportation Security Index first define the concept of transportation insecurity. Using qualitative research, candidate questions for the index are developed. Using exploratory factor analysis, a preliminary 16-question Transportation Security Index is identified that includes questions tapping into the material and relational symptoms of transportation insecurity.