While the proven Zacks Rank places an emphasis on earnings estimates and estimate revisions to find strong stocks, we also know that investors tend to develop their own individual strategies. With this in mind, we are always looking at value, growth, and momentum trends to discover great companies.Looking at the history of these trends, perhaps none is more beloved than value investing. This strategy simply looks to identify companies that are being undervalued by the broader market. Value investors use fundamental analysis and traditional valuation metrics to find stocks that they believe are being undervalued by the market at large.On top of the Zacks Rank, investors can also look at our innovative Style Scores system to find stocks with specific traits. For example, value investors will want to focus on the "Value" category. Stocks with high Zacks Ranks and "A" grades for Value will be some of the highest-quality value stocks on the market today.One company value investors might notice is Essa Bancorp (ESSA). ESSA is currently sporting a Zacks Rank of #2 (Buy), as well as a Value grade of A. The stock is trading with a P/E ratio of 8.81, which compares to its industry's average of 10.57. Over the past year, ESSA's Forward P/E has been as high as 15.20 and as low as 8.33, with a median of 10.78.Value investors also frequently use the P/S ratio. This metric is found by dividing a stock's price with the company's revenue. Some people prefer this metric because sales are harder to manipulate on an income statement. This means it could be a truer performance indicator. ESSA has a P/S ratio of 2.15. This compares to its industry's average P/S of 2.3.These figures are just a handful of the metrics value investors tend to look at, but they help show that Essa Bancorp is likely being undervalued right now. Considering this, as well as the strength of its earnings outlook, ESSA feels like a great value stock at the moment.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report ESSA Bancorp, Inc. (ESSA): Free Stock Analysis Report To read this article on Zacks.com click here.