Investors interested in Electronics - Semiconductors stocks are likely familiar with ASE Technology Hldg (ASX) and Nova Ltd. (NVMI). But which of these two stocks is more attractive to value investors? We'll need to take a closer look to find out.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 is a proven strategy that targets companies with positive earnings estimate revision trends, while our Style Scores work to grade companies based on specific traits.Currently, both ASE Technology Hldg and Nova Ltd. are holding a Zacks Rank of # 2 (Buy). This means that both companies have witnessed positive earnings estimate revisions, so investors should feel comfortable knowing that both of these stocks have an improving earnings outlook. 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.ASX currently has a forward P/E ratio of 6.80, while NVMI has a forward P/E of 22.60. We also note that ASX has a PEG ratio of 0.30. 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. NVMI currently has a PEG ratio of 2.59.Another notable valuation metric for ASX is its P/B ratio of 1.45. 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, NVMI has a P/B of 6.Based on these metrics and many more, ASX holds a Value grade of A, while NVMI has a Value grade of D.Both ASX and NVMI are impressive stocks with solid earnings outlooks, but based on these valuation figures, we feel that ASX is the superior value option right now. How to Profit from the Hot Electric Vehicle Industry Global electric car sales in 2021 more than doubled their 2020 numbers. And today, the electric vehicle (EV) technology and very nature of the business is changing quickly. The next push for future technologies is happening now and investors who get in early could see exceptional profits. See Zacks' Top Stocks to Profit from the EV Revolution >>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 ASE Technology Holding Co., Ltd. (ASX): Free Stock Analysis Report Nova Ltd. (NVMI): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research