Randomization Method
Drivers were randomized electronically via computer with treated and control groups are to be pre stratified based on demographic information provided as part of the initial club intake survey. For example, UC Status (faculty, graduate student, undergraduate etc, Housing type, EV charger in residence, Income, Age, Race, Expected number of days working on campus, Car type (plugin EV vs Hybrid). We also stratify based on the post expansion behavior. Some drivers maintained their pre-expansion charging levels, some decreased their charging, and some stopped charging on campus all together. We plan to randomize between treatment and control within these groups. Drivers are sorted into these groups based on the ratio of their maximum charge in the spring of 2024 to their maximum charge in the fall of 2024. These groups are as follows:
Attrited: Driver did not charge in the summer or fall of 2024, we believe most of these drivers are individuals who have left campus permanently, such as graduated students, or staff who are now employed elsewhere. (ratio=0)
Eliminated Campus Charging: Driver did not charge in the fall of 2024 (but did charge in the summer). We believe these are discouraged drivers who's poor experience with the network expansion resulted in their opting to charge off campus. (ratio=0)
Reduced Campus Charging: Drivers who show lower, but non zero, charging in the fall of 2024 relative to the spring of 2024. These are drivers who have shifted some, but not all, of their charging off-campus. (0<ratio<0.85)
No Change or Increase: Drivers who have approximately the same or higher charging in the fall of 2024 relative to the spring (85<ratio)