It's time to start thinking beyond Black Friday and Cyber Monday as retailers stretch out promotions beyond the traditional sales period, analysts told CNBC on Tuesday.
The comments came after a widely watched report from IBM Digital Analytics showed Cyber Monday online sales grew from last year, but at a slower pace. Digital sales jumped 8.1 percent from a year ago, compared with a 20.6 percent increase in 2013, according to the report.
But Black Friday is becoming "Black November," with retailers such as Amazon starting sales a week earlier, Mark Mahaney of RBC Capital Markets told CNBC's "Squawk Box" on Tuesday. Comparisons to past years become trickier as the data gets stretched out, he said.
"The way to do it is you have to look at the five-day period from Thanksgiving to Cyber Monday, kind of normalize for a lot of things," he said. "If you do that, it looks to us like U.S. online retail sales grew approximately 20 percent year over year."
That puts retail on track for a roughly 3 to 4 percent increase in total holiday retail sales growth, with the share of shopping shifting from in-store to online retail, he said.
Mobile browsing and sales were both up more than 30 percent from last year, according to the IBM report.
IBM measured online sales through 6 p.m. on Cyber Monday, which may not account for some retailers' promotions this year.
Wal-Mart reported a record 1.5 billion page views on its website between Thanksgiving and Cyber Monday, up from 1 billion last year. Same-day pickups on Monday increased 70 percent from last year, the retailer said.
Analysts also continued to cast doubt on a survey released by the National Retail Federation, which indicated that offline and online sales fell 11 percent between Thanksgiving Day and Sunday.
The survey lacks consistency because it polls different shoppers every year, Jim O'Sullivan, chief U.S. economist at High Frequency Economics, told "Squawk Box." He said there's no way the holiday season as a whole sees a decline, noting wage growth and improved consumer confidence.
"The backdrop for consumer spending is clearly pointing to a gain in holiday sales this year, I would argue, of at least 4 percent," he said.
Comparable store sales were up 3 percent in the week before Thanksgiving and 2 percent for the month leading into the holiday weekend, according to Applied Predictive Technologies, a cloud-based analytics firm that gathers data from registers.
APT reported that same-store retail sales on Thanksgiving Day and Black Friday were down 5.8 percent from last year.