Conservatives in Michigan gave drug tests to welfare recipients. None of them failed.

Zero.

That’s how many people in the Michigan’s Family Independence welfare program—out of 303 total test recipients—tested positive for drugs, as part of a pilot program to test subsidies recipients for substance abuse, the Guardian reports.

The Family Independence Program is Michigan’s state welfare program. It provides temporary cash assistance to families with children and pregnant women to help them pay for living expenses like food, rent and utilities. As of 2013 it was providing assistance to 122,495 state residents, including more than 87,000 children.

But Republicans in the state legislature felt that these benefits should only be given to drug-free residents. So in December 2014, the state passed (and Governor Rick Snyder signed) a bill authorizing a pilot program to screen welfare applicants for evidence of drug use.

The results from Michigan’s test mirror similar results in states that have tried to drug test state welfare recipients, like Tennessee, Missouri, and Mississippi, each of which found extremely low levels of drug use.

Drug testing for welfare recipients has proven ineffective again and again. And yet, the practice is getting more popular. According to the National Conference of State Legislatures (NCSL), as of March 28, 2016, at least 17 states had proposals in 2016 to address substance abuse and drug testing in welfare programs.

The latest state to screen welfare recipients for drugs was West Virginia, which in March created a three-year pilot program. If a caseworker has reason to believe the applicant is abusing drugs, a drug test will be ordered, according to an NCSL summary of the program. Applicants who test positive and attend substance abuse treatment, counseling, a job skills program can continue to receive benefits, although if they’re a parent they will be investigated by child protective services. Applicants who refuse the drug screen or test are ineligible automatically become ineligible to receive subsidies.

One Congresswoman, Wisconsin’s Gwen Moore, has taken a stand against drug testing welfare recipients, a practice her spokesperson called “blatantly unacceptable” and “offensive.” She recently introduced the “Top 1 percent Accountability Act,” which would require drug testing for all U.S. tax filers claiming itemized deductions of over $150,000 in a given year. In other words, if poor people should have to be drug tested before receiving government benefits, so should rich people who receive tax subsidies.

“Republicans across the country continue to implement discriminatory policies that criminalize the less fortunate and perpetuate false narratives about the most vulnerable among us,” Moore said in a statement.

Michigan’s pilot program ends on September 30. Governor Snyder is refusing to comment on its results until then.

Rob covers business, economics and the environment for Fusion. He previously worked at Business Insider. He grew up in Chicago.