We expect Anthem, Inc. ANTM to beat expectations when it reports first-quarter 2016 results on Apr 27, 2016, before the market opens.Why a Likely Positive Surprise?Our proven model shows that Anthem has the right combination of two key ingredients.Zacks ESP: Earnings ESP, which represents the difference between the Most Accurate estimate and the Zacks Consensus Estimate, is +0.30%. This is because the Most Accurate estimate of $3.35 is pegged higher than the Zacks Consensus Estimate of $3.34. This is a meaningful and leading indicator of a likely earnings beat.Zacks Rank: Anthem holds a Zacks Rank #2 (Buy). Note that stocks with a Zacks Rank of #1 (Strong Buy), 2 or 3 (Hold) have a significantly higher chance of beating on earnings.Conversely, the Sell-rated stocks (Zacks Rank #4 and 5) should never be considered going into an earnings announcement.What is Driving the Better-Than-Expected Earnings?Anthem is likely to have witnessed an increase its membership base on the back of Medicaid expansion in the Government Business segment. Medical membership is also expected to have increased in Commercial & Specialty business.Further, membership growth is likely to have been boosted, mainly due to expansion of the Affordable Care Act (ACA). These in turn is expected to have beefed up the top line.The company is likely to have favorable medical cost trends in the to-be-reported quarter. Also, the Medicare business has likely witnessed margin growth.However, the company’s in net investment income is likely to decline owing to low interest rates. Moreover, the company has witnessed membership decrease in its individual business due to the inability to experience overall market growth.With respect to the surprise trend, Anthem has delivered positive surprises in three of the last four quarters with an average beat of 9.93%.Other Stocks to ConsiderHere are some companies from the medical sector that you may want to consider as these have the right combination of elements to post an earnings beat this quarter:Amgen Inc. AMGN has an Earnings ESP of +3.52% and a Zacks Rank #3. The company is slated to report first-quarter earnings results on Apr 28.Align Technology Inc. ALGN has an Earnings ESP of +12.82% and a Zacks Rank #2. The company is slated to report first-quarter earnings results on Apr 28.AstraZeneca PLC AZN has an Earnings ESP of +5.00% and a Zacks Rank #3. The company is set to report first-quarter earnings results on Apr 29.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>>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 ASTRAZENECA PLC (AZN): Free Stock Analysis Report AMGEN INC (AMGN): Free Stock Analysis Report ANTHEM INC (ANTM): Free Stock Analysis Report ALIGN TECH INC (ALGN): Free Stock Analysis Report To read this article on Zacks.com click here.