Investors might want to bet on Northwest Pipe Co. (NWPX) , as it has been recently upgraded 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 sole determinant of the Zacks rating is a company's changing earnings picture. The Zacks Consensus Estimate -- the consensus of EPS estimates from the sell-side analysts covering the stock -- for the current and following years is tracked by the s ...