At 2:42 pm on May 6, 2010, the Dow Jones Industrial Average (DJIA) suddenly plunged by about 1,000 points within about 20 minutes. It sliced $1 trillion in investor wealth. As a result, it became known as the "Flash Crash." While the cause is far from certain, it does look like there were some major trades that tripped-up algorithmic trading systems (these use sophisticated computers for high-frequency trading).

No doubt, the Flash Crash had a jarring impact on retail investors. Could the markets be trusted? Were they safe?

The tug-of-war between the U.S. stock market's bulls and bears continues, and the next demarcation line appears to be the psychologically-significant Dow 12,000 level.

The market's bulls argue that the worst financial and economic news is behind us, and that the Dow's recent rise from about the 9,500 level in July to near 12,000 this winter is a signal by institutional investors that better days are ahead.

You can't blame investors for being a little perplexed regarding the U.S. stock market right now.

The market's bulls argue the worst financial and economic news is behind us, and that the Dow's recent rise from about the 9,500 level in July to above 11,000 early this autumn is a signal by institutional investors that better days are ahead.

Why are stocks trading at record highs? Last week we had a dismal report on unemployment, rising to above 10%. Stocks should have opened weaker today. Wrong. Stocks surged to new highs with the Dow trading at 10,147 up 126 points. Why the sudden change ot trend? The catalyst came over the weekend when the G 20 agreed to keep stimulus packages in place for their respective economies. Traders interpreted this as a buy signal because it means that more money will be sloshing around the world stimulating business and increasing profits.

Bad markets bring out "financial experts" in droves. Bad news is great for the media biz. All that confusion and panic. What a wonderful opportunity to "help" beleaguered investors understand what is going on.

What's the quality of the advice so freely given?

Historical data is not predictive, but at least it's factual. The musings of talking heads is often inaccurate, not predictive and rendered in a historical vacuum.

Here's some data that may help you sort out the mess we're in.

2000-2002 was the worst three-year period in the last thirty-eight years for both the large U.S. equity markets and the non-U.S. equity markets.

The aggregate loss for large U.S. equity stocks was 43.07%. For non-U.S. stocks it was even worse: 51.55%.

But look what happened from 2003-2007. U.S equity stocks increased in value by an aggregate of 65.57%. Non-U.S. stocks gained 109.92%.

Investors who panicked lost big. Those who stayed the course profited handsomely.

When you look at smaller sectors, the pattern is the same: Big losses were followed by big gains.

In 1973-1974, small U.S. equity stocks lost 50.8%. But in the following two years, that sector gained 110.2%.

In 1997-1998, commodities lost 49.8%. In the following two years, it gained 90.2%

In every major asset class, there has never been a sustained period of big losses where the markets have not recovered and rewarded patient investors with significant gains.

I can't predict the future. But it makes sense to understand the past.

Dan Solin is the author of The Smartest Investment Book You'll Ever Read (Perigee Books 2006) and The Smartest 401(k) Book You'll Ever Read (Perigee Books 2008).