If the stock market's recent roller-coaster ride has you feeling a bit queasy about your investments, maybe it's time you considered this question: How healthy is your portfolio?

That's the question Richard Coppa poses to investors these days. Coppa is Managing Director of Wealth Health LLC, a Roseland, NJ financial advisory firm. His clients are typically in their 50s or 60s, with investable assets between $2 million and $10 million.

Maybe you don't have millions of dollars sitting in your accounts (not yet, anyway). But if you have any money at all invested – via a 401(k) plan, your kids' college funds or anyplace else – you've almost certainly noticed the crazy volatility on Wall Street lately.

On Thursday alone, the Dow Jones Industrial Average fell 376 points, or 3.6%, to close at 10,068.01. Meanwhile, the Standard & Poor's 500 Index on Thursday gave up 43.46 points, or 3.9%, to finish at 1,071.59.

It was only back on April 26 when the Dow and the S&P 500 both hit their 2010 highs. Now, less than a month later, both benchmarks are officially in "correction" territory, having lost more than 10% of their value.

Such wild market swings are nerve-wracking for Wall Street pros and individuals investors alike. It's never any fun to watch your hard-earned money go down the tubes.

Yet, Coppa thinks that during turbulent times investors at all levels get far too bogged down on a single number – their rate of return – without proper consideration of risk, much less their overall financial health. "I always hear people comparing their returns to what the S&P 500 did," says Coppa. "But you're not the S&P, so that's comparing apples to oranges."

What investors and their advisers really should be measuring, Coppa says, is risk-adjusted returns to gauge financial well-being. To assess risk, Coppa is a big fan of using the Sharpe ratio, even if many clients don't exactly get it.

The Sharpe ratio shows how much risk is in an investment (or portfolio), and whether or not an investor was adequately compensated for taking on additional risk. The formula for calculating the Sharpe ratio is a bit complex – which may explain why even well-to-do investors would rather focus on a simple number like their annual return.

But Coppa likens the single-minded emphasis on "rate of return" to using risky methods to lose weight – and then focusing solely on the number that pops up on a bathroom scale. "You can certainly lose weight by only drinking liquids or going on any fad diet for two weeks," he notes. "But what good is it to drop 10 pounds if you mainly lose muscle, or your cholesterol and blood pressure are too high?" he asks.