Effective in early October, Fidelity Investments changed the managers of a dozen or so of its various mutual funds.

Should you care?

Intuition says we should. After all, what could be more important to the performance of a fund than the guy who’s running it?

But, this is where intuition may lead us astray. The manager of a fund may be less important than a host of other factors having to do with the manager’s fund company.

I devoted an entire column to this counter-intuitive position nearly 12 months ago, regarding a manager change at Fidelity Magellan -- Fidelity’s largest and best-known fund. To much fanfare, Harry Lange replaced Robert Stansky, who had been managing the fund since 1996.

Despite many predictions that this manager change would cause Fidelity Magellan’s previously lackluster performance to take a dramatic turn for the better, I argued, in that column, that the manager change was not that big a deal and that “Harry Lange is facing an uphill battle in trying to do any better a job than Stansky has done.”

This counter-intuitive position looks pretty good with the benefit of nearly 12 months’ hindsight. Fidelity Magellan has continued to lag the market, and by, more or less, the same margin as it underperformed in the last years of Stansky’s leadership.

The basis for that column last year was research conducted by Emory University Assistant Finance Professor Klaas Baks. He found that only a small portion of the differences in performances among funds could be attributed to the one managing those funds.

Prof. Baks reached this conclusion by constructing a database of fund managers who, at some point in their careers, switched the funds they were managing. He found that, in most cases, a manager would perform much better at the helm of one fund than another.

Furthermore, he found that funds of certain fund families tend to perform better or worse than others, regardless of who their managers were.

These results altogether suggested to Prof. Baks that the fund organization -- its research department, its trading desk, and so forth -- is more important than the manager. Testing this hunch with a complex statistical model, he found that, sure enough, about 70 percent of the differences in the performances of various funds can be attributed to the fund companies, with just 30 percent accounted for by the managers themselves.