There are many dangers in investing, such as the hot stock tip whispered to you by a colleague on a coffee break. One danger is the list of top-performing mutual funds that you'll find often in many financial periodicals. Why are such lists problematic? Let us count the ways:

For starters, they often focus on very short time frames -- say, for example, top fund performers over the past six months. That's close to meaningless, because the stock market's moves are very unpredictable over short periods. Take a basket of stocks in world-class companies, and over any six-month period (even a three-year period!), it may not fare too well. Bypass it on those grounds, and you may forgo many years of strong growth.

Then there's change. There are more than 5,000 mutual funds out there. Many of the funds at the top of one list will likely not be there the next time it's published.

Criteria are also important. What matters to you when you look for a good mutual fund? The managers' philosophy, tenure, and track record, I hope. And expense fees, tax efficiency, minimum investment amounts, etc. These are all important, yet many lists focus on just one or two of these factors -- often, just on the ultimate returns over a short period. And remember, just as a blind squirrel will find an acorn now and then, sub-par mutual funds will also occasionally have one blockbuster year. When that happens, the fund shoots to the top of various lists -- often for the only time in its life. (Trust me on this -- in my stupider investing days, I once invested in a mutual fund that earned 86% in one year. In the following years, it proceeded to lose money, and lots of it.)

Some factors are so hard (or impossible) to quantify that they are just ignored by lists. The most important of these is management. If you want to be a responsible mutual fund investor, you should spend time learning as much as you can about a fund's managers and how they think about investing. As an example, read about these three managers. And here's another intriguing fund family.

I got the idea for this piece when perusing Consumer Reports Money Adviser, which listed 25 top funds. Interestingly, No. 1, Vanguard Health Care (FUND:VGHCX), has a minimum initial investment of $25,000, effectively locking out many of us. Nos. 2 and 3, Dodge & Cox Stock (FUND:DODGX) and Fidelity Low-Priced Stock (FUND:FLPSX), are closed to new investors. A bunch of others looked promising, but there was no way to discern the managers' philosophies or approaches without digging through data on more than 20 funds.

For most people, we recommend index funds -- they're simple, and they save you the trouble of studying and selecting managed funds. Invest in an S&P 500 index fund, for example, and you're instantly invested in the likes of General Electric (NYSE:GE), Applied Materials (NASDAQ:AMAT), Dell (NASDAQ:DELL), and ExxonMobil (NYSE:XOM). But if you want to do better than index funds, take some time to learn more. As a helpful tool, consider checking out our MotleyFoolChampion Funds newsletter (which recommends funds each month and which you can painlessly try for free).

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Longtime Fool contributor Selena Maranjian does not own shares of any companies mentioned in this article.