Investors interested in Industrial Services stocks are likely familiar with Siemens AG (SIEGY) and W.W. Grainger (GWW). 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 Zacks Rank favors stocks with strong earnings estimate revision trends, and our Style Scores highlight companies with specific traits.

Currently, Siemens AG has a Zacks Rank of #1 (Strong Buy), while W.W. Grainger has a Zacks Rank of #3 (Hold). This means that SIEGY's earnings estimate revision activity has been more impressive, so investors should feel comfortable with its improving analyst outlook. But this is just one factor that value investors are interested in.

Value investors analyze a variety of traditional, tried-and-true metrics to help find companies that they believe are undervalued at their current share price levels.

The Style Score Value grade factors in a variety of key fundamental metrics, including the popular P/E ratio, P/S ratio, earnings yield, cash flow per share, and a number of other key stats that are commonly used by value investors.

SIEGY currently has a forward P/E ratio of 15.55, while GWW has a forward P/E of 26.61. We also note that SIEGY has a PEG ratio of 2.61. 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. GWW currently has a PEG ratio of 2.87.

Another notable valuation metric for SIEGY is its P/B ratio of 2.69. Investors use the P/B ratio to look at a stock's market value versus its book value, which is defined as total assets minus total liabilities. By comparison, GWW has a P/B of 14.

Based on these metrics and many more, SIEGY holds a Value grade of B, while GWW has a Value grade of C.

SIEGY 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 SIEGY is likely the superior value option right now.

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