Investors looking for stocks in the Retail - Discount Stores sector might want to consider either Dollar General (DG) or TJX (TJX). 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.Dollar General and TJX are sporting Zacks Ranks of #2 (Buy) and #3 (Hold), respectively, right now. The Zacks Rank favors stocks that have recently seen positive revisions to their earnings estimates, so investors should rest assured that DG has 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 highlights undervalued companies by looking at a variety of key metrics, including the popular P/E ratio, as well as the P/S ratio, earnings yield, cash flow per share, and a variety of other fundamentals that have been used by value investors for years.DG currently has a forward P/E ratio of 21.64, while TJX has a forward P/E of 81.75. We also note that DG has a PEG ratio of 1.75. This figure is similar to the commonly-used P/E ratio, with the PEG ratio also factoring in a company's expected earnings growth rate. TJX currently has a PEG ratio of 7.79.Another notable valuation metric for DG is its P/B ratio of 6.68. 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, TJX has a P/B of 13.51.These metrics, and several others, help DG earn a Value grade of B, while TJX has been given a Value grade of D.DG stands above TJX thanks to its solid earnings outlook, and based on these valuation figures, we also feel that DG is 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 Dollar General Corporation (DG): Free Stock Analysis Report The TJX Companies, Inc. (TJX): Free Stock Analysis Report To read this article on Zacks.com click here.