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

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, Cardinal Health (NYSE: CAH).

Cardinal Health shares have easily outperformed the S&P 500 over the last quarter-century:

Cahsp

Source: S&P Capital IQ.

Since 1987, shares have returned an average of 15.6% 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 Cardinal Health, it'd be worth $103,800.

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

Now have a look at how Cardinal Health earnings compare with S&P 500 earnings:

Cahearnings

Source: S&P Capital IQ.

Again, big outperformance. Since 1995, earnings per share have increased by an average of 9.3% per year, compared with 6% annual growth for the broader index.

What's that meant for valuations? Cardinal Health has traded for an average of 24 times earnings since 1987 -- the exact same as the broader S&P 500.

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 Cardinal Health with a four-star rating (out of five). Do you disagree? Leave your thoughts in the comment section below, or add Cardinal Health to My Watchlist.