Will Krispy Kreme Doughnuts (NYSE:KKD) report its 20th quarter in a row of positive same-store sales? If slower-growth competitors Dunkin' Brands Group (NASDAQ:DNKN) and Starbucks (NASDAQ:SBUX) are any guide, it should do so with ease. Krispy Kreme Doughnuts is scheduled to report its third-quarter results after hours on Dec. 2. Same-store sales numbers will help determine where this restaurant chain is headed.

Second-quarter results
In its last quarter's earnings release, Krispy Kreme Doughnuts reported a revenue increase of 10.7% to $102.1 million. Same-store sales rose for the 19th time in a row, up a staggering 10%. Operating income shot up 14.8% to $10.6 million. Adjusted net income leaped 17.2% to $9.6 million or $0.14 per share.

CEO James Morgan attributed the "dramatic same store sales" increase to more customers coming in simply to indulge themselves. In regard to the full year, which includes the fourth quarter, Morgan stated, "Attaining the high end of our forecasted earnings guidance appears increasingly achievable."

Krispy Kreme Doughnuts plans to "significantly increase the pace of our U.S. store expansion." This is another clue that sales continue to go well at the current locations.

The company guided for full fiscal year adjusted net income of $42 million-$45 million or $0.59-$0.63 per share. This implies that the second half of the year will show $18.3 million-$21.3 million in net income. This compares to $15.7 million last year. The "high end of the forecast" or $21.3 million would mean a 36% improvement over last year for the two quarters. It's hard not to imagine those numbers plus the company's optimism without a huge increase in same-store sales. Barring the apocalypse, it appears easily attainable.

Conference call
Turning to Krispy Kreme's prior-quarter conference call for clues, Morgan stated, "We continue to be enthusiastic about the remainder of the year." He also stated, "The driving forces continue to be inspired marketing and continuously improving in-store execution."

Then, Morgan just came right out and said it. "We are growing sales and profits within our company store segment and view promoting new doughnut use occasions as key to growing same-store sales. We know that if we give our customers an excuse to visit our stores, they will respond."

However, CFO Douglas Muir did take a bit more of a cautious tone. He stated, "I would note that while we did not have particularly easy comparisons in the first half, the comparisons are even more challenging as the year goes on."

Was Muir just being conservative? It would appear so. During the Q&A Morgan revealed that for the first three weeks of the quarter, same-store sales were already up 5.7%.

Duncan Brands and Starbucks
Often competitors who have already reported can help you understand the state of the environment. Dunkin' Brands Group reported its results on Oct. 24. Although CEO Nigel Travis described the quarter as operating in "a fairly difficult environment," Dunkin' Brands Group brought investors the goods. Total revenue increased 8.6% to $134.3 million. Same-store sales of its U.S. Dunkin' Donuts locations rose for the 14th quarter in a row, coming in at 4.2%. Adjusted earnings per share increased by 10.8% to $0.41. Dunkin' Donuts saw an increase in both guest traffic and revenue per guest.

Starbucks last reported its quarter results on Oct. 30. It, too, saw great success in the current environment. Its same-store sales were almost double those of Dunkin' Donuts coming in at 8%. Total revenue increased by 13% to $3.8 billion. Starbucks CEO Howard Schultz said it was a record year "by far" including the quarter just reported. 

Foolish final thoughts
I'd hate to go out on a limb and say that same-store sales will easily soar once again for the quarter and mark the psychologically satisfying 20th in a row, so I won't. Just take notice of this figure on Dec. 2. One thing for sure, if Krispy Kreme Doughnuts does not report a strong quarter of same-store sales then something went seriously wrong.

Nickey Friedman has no position in any stocks mentioned. The Motley Fool recommends Starbucks. The Motley Fool owns shares of Starbucks. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.