The proven Zacks Rank system focuses on earnings estimates and estimate revisions to find winning stocks. Nevertheless, we know that our readers all have their own perspectives, so we are always looking at the latest trends in value, growth, and momentum to find strong picks.

Of these, value investing is easily one of the most popular ways to find great stocks in any market environment. Value investors use a variety of methods, including tried-and-true valuation metrics, to find these stocks.

Luckily, Zacks has developed its own Style Scores system in an effort to find stocks with specific traits. Value investors will be interested in the system's "Value" category. Stocks with both "A" grades in the Value category and high Zacks Ranks are among the strongest value stocks on the market right now.

Koppers (KOP Quick QuoteKOP - Free Report) is a stock many investors are watching right now. KOP is currently sporting a Zacks Rank of #1 (Strong Buy) and an A for Value. The stock holds a P/E ratio of 6.75, while its industry has an average P/E of 17.77. Over the last 12 months, KOP's Forward P/E has been as high as 11.01 and as low as 2.58, with a median of 7.45.

Finally, we should also recognize that KOP has a P/CF ratio of 4.14. This metric focuses on a firm's operating cash flow and is often used to find stocks that are undervalued based on the strength of their cash outlook. KOP's P/CF compares to its industry's average P/CF of 11.73. KOP's P/CF has been as high as 9.39 and as low as 1.64, with a median of 4.51, all within the past year.

These are only a few of the key metrics included in Koppers's strong Value grade, but they help show that the stock is likely undervalued right now. When factoring in the strength of its earnings outlook, KOP looks like an impressive value stock at the moment.