The study tested how insurance markets work when people with different levels of risk buy insurance. They used experiments to see if offering different types of insurance contracts could help insurers attract low-risk customers. The results showed that when only full insurance was offered, low-risk customers were pushed out. Adding partial insurance didn't completely solve this problem. Instead of high and low-risk customers choosing different contracts, they ended up choosing the same one. This happened because people didn't realize how different their risks were.