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.Considering these trends, value investing is clearly one of the most preferred ways to find strong stocks in any type of 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.Kroger (KR) is a stock many investors are watching right now. KR is currently sporting a Zacks Rank of #2 (Buy), as well as a Value grade of A. The stock is trading with P/E ratio of 12.12 right now. For comparison, its industry sports an average P/E of 23.43. Over the past year, KR's Forward P/E has been as high as 14.46 and as low as 10.92, with a median of 12.46.KR is also sporting a PEG ratio of 1.92. This metric is used similarly to the famous P/E ratio, but the PEG ratio also takes into account the stock's expected earnings growth rate. KR's industry currently sports an average PEG of 3.65. KR's PEG has been as high as 2.83 and as low as 1.76, with a median of 2.32, all within the past year.Another valuation metric that we should highlight is KR's P/B ratio of 2.55. The P/B is a method of comparing a stock's market value to its book value, which is defined as total assets minus total liabilities. This stock's P/B looks attractive against its industry's average P/B of 3.61. Over the past year, KR's P/B has been as high as 3.19 and as low as 2.36, with a median of 2.72.Finally, our model also underscores that KR has a P/CF ratio of 3.78. This metric takes into account a company's operating cash flow and can be used to find stocks that are undervalued based on their solid cash outlook. KR's current P/CF looks attractive when compared to its industry's average P/CF of 11.29. Over the past 52 weeks, KR's P/CF has been as high as 5.59 and as low as 3.49, with a median of 4.67.Value investors will likely look at more than just these metrics, but the above data helps show that Kroger is likely undervalued currently. And when considering the strength of its earnings outlook, KR sticks out at as one of the market's strongest value stocks.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 The Kroger Co. (KR): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research