Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

The economy gets a boost, the markets take a dive. That's a perplexing trend that investors have to deal with as Wall Street reacts in irrational ways to data, and we're in the midst of another out-of-nowhere plunge today. The Dow Jones Industrial Average (DJINDICES:^DJI) has lost more than 200 points as of 2:25 p.m. EDT -- a painful blow to investors, as every one of its member stocks is in the red.

Yet despite all the negativity, today's not the end of the world for your portfolio.

Not a plunge to panic about
Earnings pessimism from two major Dow companies helped spark today's fall, but another, far less pressing concern also hit the markets: Wall Street's "the sky is falling" view on the impending termination of the Federal Reserve's quantitative easing. The U.S. economy showed positive signs today: New weekly jobless claims fell last week, consumer prices rose last month, and homebuilder confidence has picked up to a multiyear high in August.

That's good news for the economy -- but not for the Dow, apparently. Stimulus bond-buying has always been about lifting the U.S. economy back to its feet, and while investors everywhere should cheer what that means for the long term, short-term traders have instead chosen to lament the likelihood that a stronger economy means a hastened winding-down of Fed stimulus and its positive impact on the markets.

Sure, reduced stimulus purchases may hit the markets somewhat. But the Dow has gained 15% in 2013, and with that kind of a year already in the books, a short-term dip like today's is a small price to pay for the economy's long-term rebound. Today's drop is one more reason to keep your focus on the big picture and keep market movements in context.

That doesn't mean you shouldn't keep an eye on your stocks, however -- particularly when they're dropping as fast as Cisco (NASDAQ:CSCO), which has nosedived 7.1% today. For all the panic around the stock, Cisco actually turned in quite a strong quarter. The firm boosted its quarterly earnings per share by 16% year over year while growing revenue by 6%, beating analyst projections.

It was Cisco's upcoming forecast that turned analyst joy into worry. The company announced that it projects a maximum of 5% revenue growth for the next quarter, whereas analysts had expected growth of about 7%. Furthermore, and more troubling, Cisco said it plans to cut 4,000 workers -- nearly 5% of its total workforce. Cisco's Asia orders also fell 3% for the quarter, which is a worrying trend for the long-term future of the company. If Cisco can't keep up across the Pacific, it'll have a hard time sustaining its dominance.

Unlike Cisco, Wal-Mart (NYSE:WMT) didn't quite live up to projections: The retailer managed to grow its top and bottom lines, but more significantly, same-store sales fell 0.3% year over year in the U.S. versus expectations of a 0.7% gain. Wal-Mart also pulled back its full-year outlook -- no surprise in what has been a downbeat earnings season for retailers so far. Wal-Mart's hardly in a tough position as one of the leaders in the industry, but the firm will still need to get same-store sales growing again and advance its international revenue, which grew only 2.9% for the quarter, in order to inspire shareholders once more.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.