Comcast (NASDAQ: CMCSA) is one of the stocks most watched by Zacks.com visitors lately. So, it might be a good idea to review some of the factors that might affect the near-term performance of the stock. Over the past month, shares of this cable provider have returned +4.2%, compared to the Zacks S&P 500 composite's -4.5% change. During this period, the Zacks Cable Television industry, which Comcast falls in, has gained 10.6%. The key question now is: What could be the stock's future direction? Although media reports or rumors about a significant change in a company's business prospects usually cause its stock to trend and lead to an immediate price change, there are always certain fundamental factors that ultimately drive the buy-and-hold decision. Revisions to Earnings Estimates Rather than focusing on anything else, we at Zacks prioritize evaluating the change in a company's earnings projection. This is because we believe the fair value for its stock is determined by the present value of its future stream of earnings. We essentially look at how sell-side analysts covering the stock are revising their earnings estimates to reflect the impact of the latest business trends. And if earnings estimates go up for a company, the fair value for its stock goes up. A higher fair value than the current market price drives investors' interest in buying the stock, leading to its price moving higher. This is why empirical research shows a strong correlation between trends in earnings estimate revisions and near-term stock price movements. Comcast ...