The government decided to implement a complementary program in which all girls enrolled in secondary school in these rural areas, are provided with a bicycle. The government is interested in understanding to what extent this program works. Unfortunately, they did not run a randomized assignment of the treatment, so it is not possible to evaluate the program using a RCT. Imagine they hired you to evaluate this program.

The Peruvian government proposed to just analyze the difference in school attendance for girls receiving the bicycles before and after the program implementation (a nave estimation/comparison). Why this approach could be problematic in evaluating the true effect of the bicycle program? Briefly explain. (Hint: think about other factors affecting girls' enrollment in rural areas)