Here at Zacks, we focus on our proven ranking system, which places an emphasis on earnings estimates and estimate revisions, to find winning stocks. But we also understand that investors develop their own strategies, so we are constantly looking at the latest trends in value, growth, and momentum to find strong companies for our readers.Of these, value investing is easily one of the most popular ways to find great stocks in any market environment. Value investors rely on traditional forms of analysis on key valuation metrics to find stocks that they believe are undervalued, leaving room for profits.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 company value investors might notice is AMN Healthcare Services (AMN). AMN is currently sporting a Zacks Rank of #2 (Buy) and an A for Value. The stock is trading with a P/E ratio of 11.71, which compares to its industry's average of 14.12. Over the past 52 weeks, AMN's Forward P/E has been as high as 25.93 and as low as 9.14, with a median of 12.35.Value investors also use the P/S ratio. The P/S ratio is is calculated as price divided by sales. This is a prefered metric because revenue can't really be manipulated, so sales are often a truer performance indicator. AMN has a P/S ratio of 0.92. This compares to its industry's average P/S of 1.77.Finally, we should also recognize that AMN has a P/CF ratio of 8.18. This data point considers a firm's operating cash flow and is frequently used to find companies that are undervalued when considering their solid cash outlook. This stock's P/CF looks attractive against its industry's average P/CF of 14.59. Within the past 12 months, AMN's P/CF has been as high as 19.72 and as low as 7.79, with a median of 10.31.Investors could also keep in mind ModivCare (MODV), an Medical Services stock with a Zacks Rank of # 2 (Buy) and Value grade of A.ModivCare is currently trading with a Forward P/E ratio of 13.07 while its PEG ratio sits at 1.23. Both of the company's metrics compare favorably to its industry's average P/E of 14.12 and average PEG ratio of 1.19.Over the last 12 months, MODV's P/E has been as high as 32.73, as low as 11.28, with a median of 15.29, and its PEG ratio has been as high as 3.27, as low as 0.94, with a median of 1.29.Furthermore, ModivCare holds a P/B ratio of 3.67 and its industry's price-to-book ratio is 2.53. MODV's P/B has been as high as 6.48, as low as 3.09, with a median of 4.17 over the past 12 months.These are just a handful of the figures considered in AMN Healthcare Services and ModivCare's great Value grade. Still, they help show that the stock is likely being undervalued at the moment. Add this to the strength of its earnings outlook, and we can clearly see that AMN and MODV is an impressive value stock right now. Special Report: The Top 5 IPOs for Your Portfolio Today, you have a chance to get in on the ground floor of one of the best investment opportunities of the year. As the world continues to benefit from an ever-evolving internet, a handful of innovative tech companies are on the brink of reaping immense rewards - and you can put yourself in a position to cash in. One is set to disrupt the online communication industry. Brilliantly designed for creating online communities, this stock is poised to explode when made public. With the strength of our economy and record amounts of cash flooding into IPOs, you don’t want to miss this opportunity.>>See Zacks’ Hottest IPOs NowWant 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 AMN Healthcare Services Inc (AMN): Free Stock Analysis Report ModivCare Inc. (MODV): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research