I though this article from MIT Sloan Management Review about hiring vs. developing internal talent was quite interesting. The article posits that the characteristics of the job should have as much, if not more, influence in the decision than the people in question. Here is a relevant quote from the summary.

When ‘Stars’ Migrate, Do They Still Perform Like Stars?

Consequently, organizations should not think of talent management as a simple “build versus buy” dichotomy. Rather, there are some positions for which they can buy, and others for which they must build. Within investment banks, for example, the retail brokers (who handle individual clients) work primarily on their own. In contrast, institutional salespeople (who sell to major institutional investors such as Putnam, Vanguard and Fidelity) are more likely to perform their jobs in teams. Thus, retail brokers are more portable and can easily be hired from the outside. Institutional salespeople, however, should be developed from within, and efforts should be made to retain them.

This has lots of interesting implications for career path development, recruitment and retention.