Leaving after six years rather than three, say, means that people tend to go into better jobs with higher pay-which can also help the effectiveness of the alumni network.

四大可以好好利用这个发现。六年后而不是，比方说，三年后离开，意味着离职者有更好的工作，更高的薪水——这也有助于提高校友网络的效率。