NEW YORK (TheStreet) -- For decades, Morningstar's ratings have been a powerful force in the mutual fund industry. Funds that win a top five-star rating tend to attract assets, while most funds that receive a lowly one star soon go out of business.

Fund companies with high grades are quick to mention them in advertisements. But academic studies have shown that the ratings don't necessarily provide reliable guidance. All too often, funds that won top grades have gone on to deliver mediocre results.

Now, Morningstar has developed a new ranking system that will rate recommended funds as gold, silver or bronze. Should you ignore the new system? Not necessarily. There are good reasons to think that the latest approach could be a helpful predictor of future performance.

Old vs. New

The old star system rates funds on their risk-adjusted past performance. Funds in the top 10% of their categories win the top grade of five stars. Performers in the bottom 10% receive one star.

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The approach has some clear flaws. First, it relies solely on past performance. And as the boilerplate warnings state, past performance does not guarantee future results. In addition, the star system is purely mechanical and does not adjust for any changes in a fund's management. Say a fund wins a five-star rating in the large value category. Now the veteran manager quits and is replaced by a novice who buys only small growth stocks. Even though the outlook for the fund has changed, it will still carry the old star ratings.

To its credit Morningstar has warned against relying solely on the stars. The company has often said that past performance should only be one factor that investors consider. Describing the new gold ratings, Morningstar has again warned against relying on the system exclusively. Still, the latest ratings represent a gamble. With the forward-looking ratings, Morningstar intends to pick funds that will outperform their categories. If the system fails, then the company will have egg on its face.

What distinguishes the new approach is that it relies on the subjective judgment of the Morningstar analysts. To determine grades, the analysts must assess the quality of portfolio managers and predict future performance. Funds get top marks for having experienced managers with consistent investment disciplines. Past performance counts, but it is only one of a number of factors. The analysts prefer funds with low fees. By the end of this year, Morningstar plans to rate 1,500 funds.

The new ranking system is not the company's first attempt at making predictions about future performance. Since 1999, Morningstar has been compiling a list of about 170 funds that are designated as analyst picks.

The picks have generally performed well. After being selected for the list, most funds went on to outdo their categories during the next five years. Of the U.S. stock funds on the list, 70% surpassed their categories. Bond funds did even better. Among taxable bond funds on the list, 89% succeeded. The picks list will now disappear, replaced by the new ratings.

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The performance of the list is worth considering because it is based on the same criteria that are used for the new forward-looking ratings. If the new ratings perform as well as the analyst picks, then the gold system will prove to be a success.

Early Results

So far many of the new rankings are not surprising. The gold-rated funds include

Oakmark International

(OAKIX) - Get Report

, which has a veteran manager who outdid 95% of his competitors in the past five years.

PIMCO Total Return

(PTTRX) - Get Report

, the flagship fund of bond star Bill Gross, also won a gold rating. But there are some controversial choices.


(CFIMX) - Get Report

won a gold, even though the fund was clobbered during the downturn of 2008 and has trailed 90% of its peers in the last five years. The Morningstar analysts argue that the veteran Clipper managers have an effective strategy for finding value stocks that will produce better results in the future.

When the analysts are not sure about the outlook, they award a neutral rating. In that category is

Columbia Value & Restructuring


. The fund has a strong record, but the veteran manager is leaving. The Morningstar analysts give negative ratings to funds that seem likely to underperform. Funds with poor ratings tend to have high fees and poor track records.

Stan Luxenberg is a freelance writer specializing in mutual funds and investing. He was executive editor of Individual Investor magazine.