We expect Fitbit Inc. FIT, a leading manufacturer of wearable health and fitness tracking devices, to beat expectations when it reports first quarter 2016 results on May 4.Why a Likely Positive Surprise? Our proven model shows that Fitbit is likely to beat estimates this quarter. A stock needs to have both a positive Earnings ESP and a Zacks Rank #1 (Strong Buy), 2 (Buy) or 3 (Hold) for this to happen. Fitbit has the right combination of two key components.Zacks ESP: Fitbit currently has an Earnings ESP of +175.0%. This is because the Most Accurate estimate stands at earnings of 3 cents, while the Zacks Consensus Estimate is pegged at a loss of 4 cents.Zacks Rank: Fitbit currently carries a Zacks Rank #2, which when combined with an ESP of +175.0% make us reasonably confident of a positive surprise.We caution against stocks with a Zacks Rank #4 and 5 (Sell-rated stocks) going into the earnings announcement, especially when the company is seeing negative estimate revisions.What is Driving the Better-Than-Expected Results?Fitbit posted solid fourth-quarter results with both the top line and the bottom line exceeding the respective Zacks Consensus Estimate.Several factors are expected to drive results in the first quarter. Fitbit is rolling out Blaze and Alta on a global scale. This will, most likely result in additional manufacturing and marketing costs in the first quarter that will not impact revenues until the second quarter. So there will be significant pressure on earnings.On a positive note, there is significant untapped potential in China that Fitbit can target with its recent partnership with Tmall. The deal, which is expected to facilitate the distribution of Fitbit products in China encompasses devices, apps, social and motivational features, advice and personalized coaching. The personal coaching will be designed to bring behavioral changes in exercise, food, sleep and weight management thereby making the company a top fitness brand in the region with 10 million plus fans as soon as possible.For the first quarter Fitbit expects revenue between $420 million and $440 million. Non-GAAP diluted net income per share is expected between breakeven to 2 cents.Stocks to ConsiderFitbit is not the only firm looking up this earnings season. We also see likely earnings beats coming from these three stocks:Synopsys Inc. SNPS, with an Earnings ESP of +6.38% and a Zacks Rank #1Microchip Technology Inc. MCHP, with an Earnings ESP of +3.33% and a Zacks Rank #2Spectra Energy Partners, LP SEP,with an Earnings ESP of +2.27% and a Zacks Rank #3Want 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 SPECTRA EGY PTR (SEP): Free Stock Analysis Report SYNOPSYS INC (SNPS): Free Stock Analysis Report MICROCHIP TECH (MCHP): Free Stock Analysis Report FITBIT INC (FIT): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research