Eldorado Gold Corporation (NYSE: EGO) could be a solid addition to your portfolio given its recent upgrade to a Zacks Rank #1 (Strong Buy). This upgrade primarily reflects an upward trend in earnings estimates, which is one of the most powerful forces impacting stock prices. The Zacks rating relies solely on a company's changing earnings picture. It tracks EPS estimates for the current and following years from the sell-side analysts covering the stock through a consensus measure -- the Zacks Consensus Estimate. Individual investors often find it hard to make decisions based on rating upgrades by Wall Street analysts, since these are mostly driven by subjective factors that are hard to see and measure in real time. In these situations, the Zacks rating system comes in handy because of the power of a changing earnings picture in determining near-term stock price movements. As such, the Zacks rating upgrade for Eldorado Gold is essentially a positive comment on its earnings outlook that could have a favorable impact on its stock price. Most Powerful Force Impacting Stock Prices The change in a company's future earnings potential, as reflected ...