Investors looking for stocks in the Instruments - Control sector might want to consider either Sensata (ST) or Woodward (WWD). But which of these two companies is the best option for those looking for undervalued stocks? 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 proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.Currently, Sensata has a Zacks Rank of #2 (Buy), while Woodward has a Zacks Rank of #3 (Hold). This system places an emphasis on companies that have seen positive earnings estimate revisions, so investors should feel comfortable knowing that ST is likely seeing its earnings outlook improve to a greater extent. However, value investors will care about much more than just this.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.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.ST currently has a forward P/E ratio of 17.61, while WWD has a forward P/E of 36.13. We also note that ST has a PEG ratio of 1.60. 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. WWD currently has a PEG ratio of 2.64.Another notable valuation metric for ST is its P/B ratio of 3.39. The P/B is a method of comparing a stock's market value to its book value, which is defined as total assets minus total liabilities. By comparison, WWD has a P/B of 3.98.These are just a few of the metrics contributing to ST's Value grade of B and WWD's Value grade of C.ST is currently sporting an improving earnings outlook, which makes it stick out in our Zacks Rank model. And, based on the above valuation metrics, we feel that ST is likely the superior value option right 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 Sensata Technologies Holding N.V. (ST): Free Stock Analysis Report Woodward, Inc. (WWD): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research