Investors looking for stocks in the Business - Services sector might want to consider either Volt Information Sciences (VOLT) or HeadHunter Group PLC Sponsored ADR (HHR). But which of these two companies is the best option for those looking for undervalued stocks? Let's take a closer look.Everyone has their own methods for finding great value opportunities, but our model includes pairing an impressive grade in the Value category of our Style Scores system with a strong Zacks Rank. The proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.Right now, both Volt Information Sciences and HeadHunter Group PLC Sponsored ADR are sporting a Zacks Rank of # 2 (Buy). 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. But this is just one piece of the puzzle for value investors.Value investors also try to analyze a wide range of traditional figures and metrics to help determine whether 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.VOLT currently has a forward P/E ratio of 18.08, while HHR has a forward P/E of 41.13. We also note that VOLT has a PEG ratio of 1.21. 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. HHR currently has a PEG ratio of 1.45.Another notable valuation metric for VOLT is its P/B ratio of 3.37. 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, HHR has a P/B of 35.39.Based on these metrics and many more, VOLT holds a Value grade of B, while HHR has a Value grade of D.Both VOLT and HHR are impressive stocks with solid earnings outlooks, but based on these valuation figures, we feel that VOLT is the superior value option right now. Breakout Biotech Stocks with Triple-Digit Profit Potential The biotech sector is projected to surge beyond $775 billion by 2024 as scientists develop treatments for thousands of diseases. They’re also finding ways to edit the human genome to literally erase our vulnerability to these diseases. Zacks has just released Century of Biology: 7 Biotech Stocks to Buy Right Now to help investors profit from 7 stocks poised for outperformance. Our recent biotech recommendations have produced gains of +50%, +83% and +164% in as little as 2 months. The stocks in this report could perform even better.See these 7 breakthrough stocks now>>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 Volt Information Sciences, Inc. (VOLT): Free Stock Analysis Report HeadHunter Group PLC Sponsored ADR (HHR): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research