Investors looking for stocks in the Medical Services sector might want to consider either Tivity Health (TVTY) or Doximity (DOCS). But which of these two stocks presents investors with the better value opportunity right now? Let's take a closer look.The best way to find great value stocks is to pair a strong Zacks Rank with an impressive grade in the Value category of our Style Scores system. The Zacks Rank favors stocks with strong earnings estimate revision trends, and our Style Scores highlight companies with specific traits.Tivity Health and Doximity are both sporting a Zacks Rank of # 2 (Buy) right now. This system places an emphasis on companies that have seen positive earnings estimate revisions, so investors should feel comfortable knowing that these stocks have improving earnings outlooks. However, value investors will care about much more than just this.Value investors are also interested in a number of tried-and-true valuation metrics that help show when a company is undervalued at its current share price levels.Our Value category grades stocks based on a number of key metrics, including the tried-and-true P/E ratio, the P/S ratio, earnings yield, and cash flow per share, as well as a variety of other fundamentals that value investors frequently use.TVTY currently has a forward P/E ratio of 14.71, while DOCS has a forward P/E of 90.06. We also note that TVTY has a PEG ratio of 1.47. 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. DOCS currently has a PEG ratio of 11.26.Another notable valuation metric for TVTY is its P/B ratio of 9.41. 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, DOCS has a P/B of 12.48.Based on these metrics and many more, TVTY holds a Value grade of A, while DOCS has a Value grade of D.Both TVTY and DOCS are impressive stocks with solid earnings outlooks, but based on these valuation figures, we feel that TVTY is the superior value option right now. Zacks’ Top Picks to Cash in on Artificial Intelligence This world-changing technology is projected to generate $100S of billions by 2025. From self-driving cars to consumer data analysis, people are relying on machines more than we ever have before. Now is the time to capitalize on the 4th Industrial Revolution. Zacks’ urgent special report reveals 6 AI picks investors need to know about today.See 6 Artificial Intelligence Stocks With Extreme Upside Potential>>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 Tivity Health, Inc. (TVTY): Free Stock Analysis Report Doximity, Inc. (DOCS): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research