RICHMOND — Participants at a march in Richmond Saturday to protest in favor of a $15 an hour minimum wage rejected out of hand the economic argument that a rate that high would hurt the people it was meant to help. There was, they argued, no economic downside, and any claim to the contrary was a smokescreen by big business.

Yolanda Pierson, an Atlanta woman participating in the march, expressed the common sentiment. "It is just an excuse. They don't want to have to pay out $15," she said, adding. "They're certainly not paying themselves minimum wage."

Ty-Shawn Nunez, a New York City activist with Fight for $15, the union-funded activist group that was leading the march, said, "People are just trying to break us down about what we are doing." Asked whether he though $15 might cause problems in the future if it became that national rate, he said, "We haven't gotten there yet."

Such comments are typical of the movement for a $15 minimum wage. Organizers and activists alike simply scoff at the notion that there is any economic downside at all to more than doubling the current federally-mandated minimum wage, currently $7.25 an hour.

"Walk in our shoes," said Randy Purcell, a Durham, North Carolina activist. Employers can simply adjust if they want to, he argued. "It all depends on the people. If you have the power to change the world, wouldn't you?"

Purcell's friend and fellow Durham activist, Camilla Byrd, conceded that whether $15 might hurt the economy was something she had never really thought about. "I'm not going to agree but there might be something to it," she said.

But the possibility was not enough to make her re-think her involvement in the movement. "At the end of the day $15 is still more money in peoples' pockets," she said.

Activists think so little of the argument they usually don't even bother to acknowledge it exists. A two-day rally in Richmond hosted by Fight for $15, and its funder, the Service Employees International Union, was devoted almost entirely to testimonials by workers saying the current rate was too low for them and their families to get by and by appeals from members of the "Black Lives Matter" movement.

Economists, even some prominent liberal ones, are skeptical that an increase to $15 would be helpful, noting that increasing labor costs for employers to that level could result in cutbacks, fewer hours, lower hiring, more off-shoring of jobs or lay-offs.

The ultimate effects are unclear. The problem, economists say, is that there is no precedent for doubling the minimum so there is no real-world example to draw from. The early evidence is not encouraging.

A July study by the University of Washington regarding Seattle's increase to $11 an hour in 2015 — the first part of a phase-in for the city's eventual $15 rate — found that the higher minimum hadn't benefited the city's low-income workers.

"Seattle's low-wage workers would have experienced almost equally positive trends if the minimum wage had not increased. Although the minimum wage clearly increased wages for this group, offsetting effects on low-wage worker hours and employment muted the impact on labor earnings," the study found.

The city's employment rate was at 4.3 percent in April 2015 when the $11 rate went into effect. By May of this year, Seattle unemployment was 4.8 percent, nearly half a point higher.