The Dow Jones Industrial Average (INDEX: ^DJI) is struggling to find its way as investors and traders mull over conflicting economic evidence. While the index started the day higher, it has since jumped back and forth between positive and negative territory.

A mixed bag of news
On the positive front, the productivity of U.S. workers climbed more than initially estimated in the second quarter. Figures released today by the U.S. Department of Labor revealed that the measure of employee output per hour climbed at a 2.2% annual rate. This follows a 0.5% decline in the first quarter and handily beats estimates for a 1.8% increase.

Shares in industrial companies like Alcoa (NYSE: AA) and General Electric (NYSE: GE) are higher on the heels of this news, up 0.92% and 0.63%, respectively, in intraday trading. Yet the index's biggest winner is Disney (NYSE: DIS), up 2.5% on the day as it continues basking in the success of The Avengers, which has brought in more than $1.5 billion in global box office sales and was recently slated for a sequel.

On the negative front, investors continue to digest two pieces of bad news from earlier in the week. The first concerns a report released yesterday from the Institute of Supply Management suggesting that manufacturing activity contracted in the month of August. As I noted yesterday, this marked the third consecutive month of declines and was the worst reading in more than three years.

The second piece of bad news came after the markets had closed yesterday, when economic bellwether Fedex cut its earnings forecast for the current quarter, citing "weakness in the global economy." Shares in the company -- as well as its competitor UPS -- tumbled in after-hours trading following the announcement, and both remain depressed by nearly 2% today.

In terms of Dow components, today's biggest loser is American Express (NYSE: AXP), down approximately 2.5%. While there doesn't appear to be a specific impetus for the decline, the company's performance is in line with the industry, as all major card issuers are down on the day. My colleague Matt Thalman postulated that this could be due to Apple's imminent and long-awaited release of the iPhone 5, as plastic may "soon become a thing of the past." According to our expert on everything Apple, Evan Niu, the company has "now sent out its official press invites to media for its special iPhone event confirming the date [of Sept. 12]."

Complacency is your enemy
Don't let today's meandering of the Dow lull you into a state of complacency, as the remainder of the week is chock-full of potentially destabilizing events.

The European Central Bank meets tomorrow and is widely expected to announce a purportedly unlimited bond-buying program aimed at reclaiming control of the continent's sovereign bond yields. And on Friday, the Labor Department releases the much-anticipated jobs numbers for August. Early estimates suggest that employers added only 120,000 jobs, well below the amount needed to have a positive impact on the current 8.3% unemployment rate.

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