金日净水器骗局揭秘:请帮我翻译一下

As with any study, there are potential limitations to the findings. First, although statistical techniques were used to control for differences in the two groups, the conclusions would be stronger if the two groups were more similar. There appears to be potential for self-selection bias in the schools that participate with the Advocate Unit. The Advocate Unit schools are different from the population in the size of the loans, level of family contribution, amount of financial aid received, degree offerings (e.g., associate’s versus bachelor’s), and reasons the students left school. It is possible that the true effect of the Advocate Unit is suppressed due to these differences. The length of the study also needs consideration. Although a longitudinal effect was found, it would most likely be useful to extend the study to see if the positive effects from Advocate Unit participation are sustainable.