Causality vs. Correlation: Rethinking Research Design in the Case of Pedestrian Environments and Walking
This paper investigates the causal effect of pedestrian environments on walking behavior and focuses on the issue of research design. The paper differentiates between two types of research designs:treatment-based and traveler-based. The first approach emphasizes the variation of the treatment (pedestrian environments), and generally compares distinct neighborhoods, such as urban vs. suburban or transit-oriented vs. auto-dependent. The second approach emphasizes the homogeneity of subject (pedestrians), and aims at the same pedestrian under different environments normally due to home relocation, or the improvement of pedestrian environments.
This paper presents a third method, following a traveler-based research design while providing the pedestrian multiple walking paths with different pedestrian environments.