Investing isn't easy. Even Warren Buffett counsels that most investors should invest in a low-cost index like the S&P 500. He says that way "you'll be buying into a wonderful industry, which in effect is all of American industry."

But there are, of course, companies whose long-term fortunes differ substantially from the index. In this series, we look at how individual stocks have performed against the broad S&P 500.

Step on up, Anadarko Petroleum (NYSE: APC).                            

Anadarko Petroleum shares have easily outperformed the S&P 500 over the last quarter-century, with most of the outperformance occurring in the last decade:

Apcsp

Source: S&P Capital IQ.

Since 1987, shares have returned an average of 11.1% a year, compared with 9.7% a year for the S&P (both include dividends). That difference adds up fast. One thousand dollars invested in the S&P in 1987 would be worth $19,200 today. In Anadarko Petroleum, it'd be worth $29,300.

Dividends accounted for a lot of those gains. Compounded since 1987, dividends have made up about 19% of Anadarko Petroleum's total returns. For the S&P, dividends account for 39% of total returns.

Now have a look at how Anadarko Petroleum earnings compare with S&P 500 earnings:

Apcearnings

Source: S&P Capital IQ.

Pretty average here, albeit with much more volatility. Since 1995, Anadarko Petroleum earnings per share have increased by an average of 6.3% a year, compared with 6% a year for the broader index.

What's that meant for valuations? Anadarko Petroleum has traded for an average of 40 times earnings since 1987 -- above the 24 times earnings of the broader S&P 500. It's far different today, however. Anadarko currently trades for about 17 times next year's expected earnings.

Through it all, shares have been strong performers over the last quarter-century.  

Of course, the important question is whether that will continue. That's where you come in. Our CAPS community currently ranks Anadarko Petroleum with a four-star rating (out of five). Care to disagree? Leave your thoughts in the comment section below, or add Anadarko Petroleum to My Watchlist.