Investors interested in Medical Services stocks are likely familiar with Elevance Health (ELV) and Progyny (PGNY). But which of these two companies is the best option for those looking for undervalued stocks? Let's take a closer look.There are plenty of strategies for discovering value stocks, but we have found that pairing a strong Zacks Rank with an impressive grade in the Value category of our Style Scores system produces the best returns. The Zacks Rank favors stocks with strong earnings estimate revision trends, and our Style Scores highlight companies with specific traits.Currently, both Elevance Health and Progyny are holding a Zacks Rank of # 2 (Buy). Investors should feel comfortable knowing that both of these stocks have an improving earnings outlook since the Zacks Rank favors companies that have witnessed positive analyst estimate revisions. But this is only part of the picture for value investors.Value investors analyze a variety of traditional, tried-and-true metrics to help find companies that they believe are undervalued at their current share price levels.The Value category of the Style Scores system identifies undervalued companies by looking at a number of key metrics. These include the long-favored P/E ratio, P/S ratio, earnings yield, cash flow per share, and a variety of other fundamentals that help us determine a company's fair value.ELV currently has a forward P/E ratio of 17.71, while PGNY has a forward P/E of 125.02. We also note that ELV has a PEG ratio of 1.47. 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. PGNY currently has a PEG ratio of 5.94.Another notable valuation metric for ELV is its P/B ratio of 3.42. The P/B ratio pits a stock's market value against its book value, which is defined as total assets minus total liabilities. For comparison, PGNY has a P/B of 9.13.These metrics, and several others, help ELV earn a Value grade of A, while PGNY has been given a Value grade of C.Both ELV and PGNY are impressive stocks with solid earnings outlooks, but based on these valuation figures, we feel that ELV is the superior value option right now. Zacks Names "Single Best Pick to Double" From thousands of stocks, 5 Zacks experts each have chosen their favorite to skyrocket +100% or more in months to come. From those 5, Director of Research Sheraz Mian hand-picks one to have the most explosive upside of all. It’s a little-known chemical company that’s up 65% over last year, yet still dirt cheap. With unrelenting demand, soaring 2022 earnings estimates, and $1.5 billion for repurchasing shares, retail investors could jump in at any time. This company could rival or surpass other recent Zacks’ Stocks Set to Double like Boston Beer Company which shot up +143.0% in little more than 9 months and NVIDIA which boomed +175.9% in one year.Free: See Our Top Stock and 4 Runners Up >>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 Elevance Health, Inc. (ELV): Free Stock Analysis Report Progyny, Inc. (PGNY): Free Stock Analysis ReportTo read this article on Zacks.com click here.Zacks Investment Research