Two factors often determine stock prices in the long run: earnings and interest rates. Investors can't control the latter, but they can focus on a company's earnings results every quarter.We know earnings results are vital, but how a company performs compared to bottom line expectations can be even more important when it comes to stock prices, especially in the near-term. This means that investors might want to take advantage of these earnings surprises.Now that we know how important earnings and earnings surprises are, it's time to show investors how to take advantage of these events to boost their returns by utilizing the Zacks Earnings ESP filter.The Zacks Earnings ESP, ExplainedThe Zacks Expected Surprise Prediction, or ESP, works by locking in on the most up-to-date analyst earnings revisions because they can be more accurate than estimates from weeks or even months before the actual release date. The thinking is pretty straightforward: analysts who provide earnings estimates closer to the report are likely to have more information.Now that we understand the basic idea, let's look at how the Expected Surprise Prediction works. The ESP is calculated by comparing the Most Accurate Estimate to the Zacks Consensus Estimate, with the percentage difference between the two giving us the Zacks ESP figure.Bringing together a positive earnings ESP alongside a Zacks Rank #3 (Hold) or better has helped stocks report a positive earnings surprise 70% of the time. Furthermore, by using these parameters, investors have seen 28.3% annual returns on average, according to our 10 year backtest.Stocks with a ranking of #3 (Hold), or 60% of all stocks covered by the Zacks Rank, are expected to perform in-line with the broader market. Stocks with rankings of #2 (Buy) and #1 (Strong Buy), or the top 15% and top 5% of stocks, respectively, should outperform the market; Strong Buy stocks should outperform more than any other rank.Should You Consider Mosaic?The last thing we will do today, now that we have a grasp on the ESP and how powerful of a tool it can be, is to quickly look at a qualifying stock. Mosaic (MOS) holds a #1 (Strong Buy) at the moment and its Most Accurate Estimate comes in at $0.51 a share 14 days away from its upcoming earnings release on May 3, 2021.By taking the percentage difference between the $0.51 Most Accurate Estimate and the $0.49 Zacks Consensus Estimate, Mosaic has an Earnings ESP of 3.06%. Investors should also know that MOS is just one of a large group of stocks with positive ESPs. All of these qualifying stocks can be filtered by ESP, Zacks Rank, % Surprise (Last Qtr.), and Reporting date.Now that you know how to use the Zacks Earnings ESP to your advantage, make sure to check out the Earnings ESP Home Page for even more earnings related strategies to create a winning portfolio.Find Stocks to Buy or Sell Before They're ReportedUse the Zacks Earnings ESP Filter to turn up stocks with the highest probability of positively, or negatively, surprising to buy or sell before they're reported for profitable earnings season trading. Check it out here >>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 The Mosaic Company (MOS): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research