Investors looking for stocks in the Medical - Hospital sector might want to consider either Universal Health Services (UHS) or Acadia Healthcare (ACHC). But which of these two stocks is more attractive to value investors? We'll need to take a closer look to find out.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 proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.Both Universal Health Services and Acadia Healthcare have a Zacks Rank of # 2 (Buy) right now. The Zacks Rank favors stocks that have recently seen positive revisions to their earnings estimates, so investors should rest assured that both of these companies 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.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.UHS currently has a forward P/E ratio of 11.94, while ACHC has a forward P/E of 25.03. We also note that UHS has a PEG ratio of 1.83. This popular metric is similar to the widely-known P/E ratio, with the difference being that the PEG ratio also takes into account the company's expected earnings growth rate. ACHC currently has a PEG ratio of 6.95.Another notable valuation metric for UHS is its P/B ratio of 1.87. The P/B ratio is used to compare a stock's market value with its book value, which is defined as total assets minus total liabilities. For comparison, ACHC has a P/B of 2.48.These are just a few of the metrics contributing to UHS's Value grade of A and ACHC's Value grade of C.Both UHS and ACHC are impressive stocks with solid earnings outlooks, but based on these valuation figures, we feel that UHS is the superior value option right now. Time to Invest in Legal Marijuana If you’re looking for big gains, there couldn’t be a better time to get in on a young industry primed to skyrocket from $17.7 billion back in 2019 to an expected $73.6 billion by 2027. After a clean sweep of 6 election referendums in 5 states, pot is now legal in 36 states plus D.C. Federal legalization is expected soon and that could be a still greater bonanza for investors. Even before the latest wave of legalization, Zacks Investment Research has recommended pot stocks that have shot up as high as +285.9%. You’re invited to check out Zacks’ Marijuana Moneymakers: An Investor’s Guide. It features a timely Watch List of pot stocks and ETFs with exceptional growth potential.Today, Download Marijuana Moneymakers FREE >>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 Universal Health Services, Inc. (UHS): Free Stock Analysis Report Acadia Healthcare Company, Inc. (ACHC): Free Stock Analysis Report To read this article on Zacks.com click here.