Scientists and science fans will converge on Washington on Saturday for a march aimed at defending the role of science, highlighting the importance of evidence and expertise in policymaking and demanding that the U.S. government not cut research funding. Part of the rhetoric leading up to the March for Science has focused on scientists as reluctant protesters forced to take action, and how unusual it is for academics and researchers to join a political movement in their professional capacities. That may well be true, but it overshadows an important fact that helps put the march into a broader context: It’s pretty rare for people in any occupation to march on their field’s behalf.

“There’s lots of nurse labor action, but that typically happens around labor disputes with specific hospitals and local communities,” said John McCarthy, a professor of sociology at Penn State University who specializes in the study of collective behavior and social movements. There haven’t been many protests that addressed the reputational concerns of a single occupation, or its big-picture finances, in a broad way — and especially not at a national scale.

We know that’s true because of a database that McCarthy built, with researchers from Stanford, which catalogues 24,398 collective-action events in the U.S. from 1960 through 1995, as recorded in The New York Times. Called the Dynamics of Collective Action, the database tracks details such as the type of organizing group, the motivating issues and where each event occurred. Not all the events are protests like the March for Science — some of the entries commemorate press conferences, others the start of landmark lawsuits. And the database has some important limitations, not the least of which is that it includes only events the Times saw fit to print. There’s probably a lot missing.

But the database can help characterize trends, at least through its 1995 end point, and one of the data points it tracks is the collective identity of the primary group that organized the event. What characteristics did the organizers share? What identity motivated their grievances, their choice of target and their goals? The data shows that, while the science marchers are unusual, they aren’t alone.

A shared occupation was the fourth-most-common group identity, accounting for 1,875 events. But only 33 percent of those events involved typical protest activities — things such as rallies, marches and picketing. When people organize around their jobs, they’re usually either doing it in ways that don’t involve taking to the streets en masse or, if they are marching, their action is centered on a localized workers strike and not a broader movement seeking respect and funding that is aimed at the government and the public at large.

GROUP TOTAL EVENTS SHARE OF EVENTS THAT INVOLVED TYPICAL PROTEST ACTIVITIES Students 2,613 62% African-Americans 3,831 58 Social movement actors 6,743 52 Women 835 51 Local residents 1,555 44 White Americans 1,186 36 Occupational groups 1,875 33 Collective action events in the U.S., 1960-95 Source: Dynamics of Collective Action database

In Washington, there were only 45 events in the database over 36 years that were organized by occupation-linked groups and involved typical protest activities. And not even all of those consisted of occupational groups marching on their own behalf. For instance, on April 22, 1968, clergy members held a vigil on Capitol grounds to protest work requirements for welfare recipients. An additional six events were organized by federal government workers, for whom D.C. is the logical place to address grievances against their employer.

But as it turns out, when scientists travel from across the country to ask their government for respect and funding, the group they will most closely be emulating is farmers.

OCCUPATIONAL GROUP NUMBER OF D.C. PROTESTS Farmers 16 Government workers 6 Union members 3 Artists and musicians 2 Media 2 Cotton mill workers 2 Religious/clergy 2 Occupation-related protests in Washington, 1960-95 Source: Dynamics of Collective Action database

Farmers took to Washington at least 16 times in that 36-year stretch, making them the occupational group with the highest number of D.C. protests by far. All but three of these events happened in the late 1970s. This was the beginning of a long crisis period for Midwestern farmers, when previously high grain prices began to plummet and many farms went into foreclosure. Farmers resented the withdrawal of government funding for agricultural subsidies. They felt like the millions of Americans who benefited from their hard work didn’t appreciate it. These protests were, like the March for Science, a demand for respect, appreciation and funding by an occupation in which workers felt they were being discounted.

Now, it’s unlikely that scientists will release 50 goats on the Capitol steps or drive a convoy of tractors around the White House. But the spirit behind their grievances and those of the ’70s farmers match up pretty well. Which means the scientists should also probably pay some attention to how the farmers did, and didn’t, succeed in their campaigns.

The marches of scientists and the tractorcades of farmers are consistent with the symbolism that protests on Washington’s National Mall are all about, said Lisa Benton-Short, a geography professor at George Washington University who has studied the cultural meaning of the Mall and protests there. The Mall, she told me, is where Americans go when they want to change the national identity, or remind other Americans of values they believe we should all share. The farm protests were about reminding Americans of their agricultural roots and the importance of farmers in the lives of average people who, largely, no longer grow their own food. Similarly, Benton-Short said, for scientists, “this is a march about protesting a rhetoric that marginalizes or dismisses science and the professionals that have dedicated their lives to understanding climate change and human health.”

But, she cautioned, influencing national identity isn’t the same thing as immediately solving specific, pressing policy concerns. The farmers built a nationwide solidarity movement that culminated in the 1985 creation of the annual Farm Aid concerts, organized by Willie Nelson, John Mellencamp and Neil Young. But it was a decade after their first, 1977, protests before Congress passed a bill to help protect farmers from foreclosure. And another focus of those ’70s protests — parity, or setting prices for agricultural products based on the cost of producing them, rather than just by what people will pay for them — has never been achieved. Forty years later, it’s still one of the top goals for the American Agricultural Movement, the lobbying organization that grew out of the protests.

Starting national conversations by protesting on the Mall is a longstanding tradition, and it’s important, Benton-Short said. But change doesn’t usually happen quickly afterwards, she said, citing early 20th century women’s suffrage marches as an example. The goal is really to make it clear to politicians that this is something people care about, and to start the process of creating political pressure. When it comes to specific political goals, Benton-Short wasn’t sure what the March on Science hoped to accomplish. “I know the big picture,” she said. “But what will be interesting is to also see the reaction to that. How congressmen, senators and Republicans interpret the day and the messages they walk away with.”