Here at Zacks, our focus is on the proven Zacks Rank system, which emphasizes earnings estimates and estimate revisions to find great stocks. Nevertheless, we are always paying attention to the latest value, growth, and momentum trends to underscore strong picks.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.Zacks has developed the innovative Style Scores system to highlight stocks with specific traits. For example, value investors will be interested in stocks with great grades in the "Value" category. When paired with a high Zacks Rank, "A" grades in the Value category are among the strongest value stocks on the market today.One stock to keep an eye on is Big Lots (BIG). BIG is currently sporting a Zacks Rank of #2 (Buy), as well as a Value grade of A.Investors will also notice that BIG has a PEG ratio of 1.58. This popular figure is similar to the widely-used P/E ratio, but the PEG ratio also considers a company's expected EPS growth rate. BIG's industry has an average PEG of 2.75 right now. Within the past year, BIG's PEG has been as high as 3.78 and as low as 0.50, with a median of 1.02.Value investors also frequently use the P/S ratio. This metric is found by dividing a stock's price with the company's revenue. This is a prefered metric because revenue can't really be manipulated, so sales are often a truer performance indicator. BIG has a P/S ratio of 0.33. This compares to its industry's average P/S of 0.96.These figures are just a handful of the metrics value investors tend to look at, but they help show that Big Lots is likely being undervalued right now. Considering this, as well as the strength of its earnings outlook, BIG 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 Big Lots, Inc. (BIG): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research