Waves of demonstrations aimed at eliminating racial injustice have been sweeping through much of the United States just as the holiday shopping season has begun. And early numbers indicate that retail sales have been disappointing.

Both developments have attracted considerable attention. But for the most part, major media outlets have treated them as separate phenomena — like events taking place on two different continents — even though thousands of protesters declared explicitly that they were boycotting stores on Black Friday.

So, what about the obvious question: Have the protests contributed to the sales decline?

Vast quantities of data about American consumers are churned out daily, and you might expect that it would provide an answer. Businesses, investors, academics and policy makers rely on that data. The problem is that for illuminating answers, you need to ask the right questions.

Last Sunday, for example, the National Retail Federation, a trade association, released its annual survey of holiday shopping. As usual, it was heavily covered.

The federation announced that for the holiday weekend through Saturday, nationwide year-over-year sales had dropped 11 percent, a startlingly big number. The extensive survey data, along with anecdotal information compiled by the federation’s chief executive, Matthew R. Shay, suggested a variety of reasons for the sales decline. These included pre-Thanksgiving discounts by retail chains, ever-present cheap deals on the Internet and the still-shaky fiscal condition of many Americans who have not entirely recovered from the recession.

But when I listened to a recording of the conference call held by the federation with reporters on Sunday afternoon, I found that the conversation didn’t include a single word about the nationwide protests that closed some malls over the holiday weekend, obstructed traffic in big cities and flooded social media with appeals for Americans to stop shopping. Events like those weren’t examined by the survey. Protest wasn’t on the federation’s radar.

“That’s not an area we’ve ever gotten into,” said Kathy Grannis, a spokeswoman for the federation, when I asked her about it last week. The federation has traditionally avoided touchy subjects, leaving it up to the retail chains in its membership to talk about them if they so choose. And last week, the big chains generally weren’t saying much about the boycott.

Macy’s, which was the target of a demonstration on Black Friday at its flagship store in Herald Square, declined to comment. Tara Darrow, a spokeswoman for Nordstrom, said that chain wouldn’t comment about its holiday sales, either. “In relation to the recent protests,” she said, “we have experienced some activity at a few of our stores across the country, but the impact has been really minimal.”

Perhaps the lack of solid data is why most mainstream news reports didn’t examine a possible link between the protests and flagging sales. These apparent omissions lit up Facebook and Twitter. For example, in a Twitter post on Wednesday, Shaun Abreu, a recent graduate of Columbia University, said: “The media is straight up downplaying the impact #BoycottBlackFriday had on the 11% decrease in sales. Let’s take it through Christmas then.”

I asked some of the boycott organizers how effective they thought they had been. They were able to provide detailed information about their roles in promoting the protests on social media but had no data about the effects of their efforts on retailers.

Rahiel Tesfamariam, the founder and publisher of the online magazine Urban Cusp, created the hashtag #NotOneDime on Twitter on Nov. 24, after a St. Louis County grand jury decided not to indict Darren Wilson, the police officer who this summer shot and killed Michael Brown, an unarmed man in Ferguson, Mo. Her slogan has been repeated across the Internet.

“The power structure isn’t listening to us in the streets or in the courts, so we are going to have to do it with our buying power,” she said in an interview. With a new hashtag, #BlackDecember, she is calling for people to buy from black-owned businesses.

Separately, a Los Angeles-based network called the Blackout for Human Rights used the hashtag #BlackoutBlackFriday on Twitter in early November, according to Michael Latt, a spokesman for the group. The group decided to include a Black Friday boycott in its protests “because America speaks the language of money, and that’s something that everybody can understand,” Mr. Latt said. But he and Ms. Tesfamariam said that they had not tried to come up with any numbers that might prove they were having an economic impact.

“We think the impact is obvious,” Mr. Latt said. And, he said, protests and, perhaps, boycotts will continue. They are now focused on the decision on Wednesday of a Staten Island grand jury not to indict a police officer in the death of Eric Garner, another unarmed black man, who died after being placed in a chokehold.

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There’s no doubt that such protests can galvanize public opinion. But what effects are they having in this prime shopping season? This brings us back to the data. Early shopping numbers are notoriously unreliable, and the National Retail Federation’s 11 percent decline was only an estimate based on a survey of 4,631 people. It divided respondents by income level and age — but not by race — and asked them about their intended and actual purchases, both in bricks-and-mortar stores and online. On the basis of their answers, it extrapolated aggregate numbers for the entire American economy.

The questions in this year’s survey were decided on Nov. 17, Ms. Grannis said, before the grand jury decision in the Ferguson case. In any event, no questions about social unrest have ever been included in the survey. “It’s just an estimate,” she said. “It’s our best shot.”

Other data providers have come up with varying numbers, generally pointing to a decline in bricks-and-mortar sales, along with an increase in online sales, at the start of the shopping season.

For example, data provided by Applied Predictive Technologies, based on sales by national chains with annual revenue of at least $500 million, showed a 3.5 percent decline in same-store sales nationwide for the Thanksgiving weekend through Sunday. Among the top 25 metropolitan areas in the United States, the St. Louis region — perhaps the one most deeply affected by the trauma in Ferguson, a St. Louis suburb — had the second-worst performance, a 9 percent decline from the same period the previous year. Jonathan Marek, a senior vice president at the company, said he had no way of knowing what impact the demonstrations and the boycott might have had. “It’s logical to assume it all had an impact, maybe half a percent, something like that, but I don’t really know,” he said.

At this point, I don’t know either. But the question certainly seems worth asking.

The Strategies column last Sunday, about how holiday retail sales may have been affected by recent demonstrations against racial injustice, referred incorrectly to the death of Eric Garner after a confrontation with the police on Staten Island. He died after being placed in a chokehold; he did not die in a shooting.