The “Families Belong Together” march this past weekend involved a tremendous amount of last-minute coordination and organizing. In just 12 days, MoveOn, the American Civil Liberties Union, the National Domestic Workers Alliance and the Leadership Conference on Civil and Human Rights led a diverse coalition of organizations that mobilized over 400,000 people, based on a preliminary count from the Counting Crowds project, at more than 750 events across the country, according to numbers released by MoveOn and the National Domestic Workers Alliance.

As described below, I have been studying who is attending the protests and marches since President Trump’s inauguration. Two points stood out at this event. First, most of those who attended were not new to protesting. Second, many were strongly connected to an organization involved in mobilizing for the march. Let me explain.

Here’s how I did my research

As part of my ongoing research on the resistance to the Trump administration, I have been working with a team to survey attendees at all the large-scale protest events in Washington since Trump’s inauguration. So far, the complete data set includes surveys collected from 1,946 protest participants.

In this case, we surveyed protesters at the Families Belong Together march in Washington in the 104-degree heat Saturday. By snaking through the crowd and sampling every fifth person at designated increments within the staging area, we gathered a field approximation of a random sample. During this weekend’s march, my team collected a sample of 201 people randomly selected throughout the crowd and had them fill out electronic surveys on our tablets while they were lining up, listening to speakers and waiting to march.

Who was there? Women, the highly educated — and involved citizen activists.

Like other protests we’ve sampled, the Families Belong Together march attracted more women than men; in this case, 71 percent were women, compared with 85 percent at the 2017 Women’s March. Participants were highly educated; 84 percent had a BA or higher. More than half of the participants this weekend — 56 percent of the crowd — had completed a graduate degree, the highest percentage so far. The Families Belong Together march was also predominantly white, with 70 percent white compared with 77 percent at the Women’s Marches in 2017 and 2018. Overall, we found the crowd was 9 percent Latino, 7 percent black, 5 percent Asian/Pacific Islander and 8 percent multiracial.

Unlike the previous marches, very few participants — only 9 percent — were first-time protesters. In the past 18 months, participants at the Families Belong Together march had marched for women’s rights (75 percent in 2017 and 51 percent in 2018), science (31 percent), and the March for Our Lives (56 percent), among others. As we’ve seen at the other marches, the Families Belong Together participants were predominantly left-leaning. Eight percent identified as ideologically moderate, and 3 percent identified as right-leaning.

While the march did not turn out a high percentage of new protesters or ideological moderates, a third of the participants reported being a member of a group that was involved in organizing the event.

All participants in the march reported being very politically engaged, but those who were members of organizations were much more so. Those who reported being active members of organizations — attending meetings and participating in group activities — were much more likely to have contacted an elected official (88 percent vs. 65 percent of nonmembers) and attended a town hall meeting (88 percent vs. 46 percent of nonmembers). These rates of participation are significantly higher than the national average for ordinary Americans.

Three people in our sample reported running for political office in the past year; all three were active members of a group in the organizing coalition.

These groups are not just organizing marches; they’re channeling citizen activism

Many groups in the organizing coalition are increasingly focused on political activities leading up to the midterm elections. What we found, then, is evidence that these organizations are not just mobilizing people to march in the streets; they are also providing channels through which individuals can become politically active in their own communities and districts.

Dana R. Fisher is a professor of sociology at the University of Maryland. Her book-in-progress, “American Resistance,” will be published by Columbia University Press after the midterm elections.