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.Life and the stock market are both about expectations, and rising above what is expected is often rewarded, while falling short can come with negative consequences. Investors might want to try to capture stronger returns by finding positive earnings surprises.The ability to identify stocks that are likely to top quarterly earnings expectations can be profitable, but it's no simple task. Here at Zacks, our Earnings ESP filter helps make things easier.The Zacks Earnings ESP, ExplainedThe Zacks Earnings ESP, or Expected Surprise Prediction, aims to find earnings surprises by focusing on the most recent analyst revisions. The basic premise is that if an analyst reevaluates their earnings estimate ahead of an earnings release, it means they likely have new information that could possibly be more accurate.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.When we join a positive earnings ESP with a Zacks Rank #3 (Hold) or stronger, stocks posted a positive bottom-line surprise 70% of the time. Plus, this system saw investors produce roughly 28% annual returns on average, according to our 10 year backtest.Most stocks, about 60%, fall into the #3 (Hold) category, and they are expected to perform in-line with the broader market. Stocks with a #2 (Buy) and #1 (Strong Buy) rating, or the top 15% and top 5% of stocks, respectively, should outperform the market, with Strong Buy stocks outperforming more than any other rank.Should You Consider Genuine Parts?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. Genuine Parts (GPC) holds a #3 (Hold) at the moment and its Most Accurate Estimate comes in at $2.05 a share 24 days away from its upcoming earnings release on October 20, 2022.GPC has an Earnings ESP figure of +0.82%, which, as explained above, is calculated by taking the percentage difference between the $2.05 Most Accurate Estimate and the Zacks Consensus Estimate of $2.03. Genuine Parts is one of a large database of stocks with positive ESPs. Make sure to utilize our Earnings ESP Filter to uncover the best stocks to buy or sell before they've reported.GPC is part of a big group of Auto, Tires and Trucks stocks that boast a positive ESP, and investors may want to take a look at Cummins (CMI) as well.Cummins, which is readying to report earnings on November 1, 2022, sits at a Zacks Rank #3 (Hold) right now. It's Most Accurate Estimate is currently $4.93 a share, and CMI is 36 days out from its next earnings report.For Cummins, the percentage difference between its Most Accurate Estimate and its Zacks Consensus Estimate of $4.82 is +2.26%.Because both stocks hold a positive Earnings ESP, GPC and CMI could potentially post earnings beats in their next reports.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 >> 5 Stocks Set to Double Each was handpicked by a Zacks expert as the #1 favorite stock to gain +100% or more in 2021. Previous recommendations have soared +143.0%, +175.9%, +498.3% and +673.0%. Most of the stocks in this report are flying under Wall Street radar, which provides a great opportunity to get in on the ground floor.Today, See These 5 Potential Home Runs >>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 Genuine Parts Company (GPC): Free Stock Analysis Report Cummins Inc. (CMI): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research