Public school officials across Michigan are secretly spending tax dollars on political lobbying, according to a report by the Michigan-based Mackinac Center.

Education administrators are required by Michigan law to make public their lobbying expenditures, but that isn’t happening in Oakland, Macomb and Wayne County school districts. Officials there are handing hundreds of thousands of dollars in dues payments to the Tri-County Alliance, a political lobbying group made up of school superintendents, but few report it as lobbying, according to Mackinac.

TCA brings in about $210,000 annually, according to tax documents, three-quarters of which comes from membership dues paid with public money. But only 34 districts reported in their transparency documents that they sent money to the lobbying group at all, according to Mackinac.

“In practice, this means that these public school districts can appear less politically active than they really are, while simultaneously spending hundreds of thousands of dollars on political lobbying,” wrote Jarrett Skorup, a research associate with the think tank.

In addition to membership dues, the Oakland School District, which reported sending $2,275 to TCA in the 2011-2012 school year, provides TCA with its office needs and even employees, under the heading of “annual support costs.” Those costs are split between the Tri-County districts.

“Taxpayer dollars are being used to lobby for more taxpayer dollars with little scrutiny from the people funding it. By creating a nonprofit, southeastern Michigan school districts are able to fund a political lobbying arm and avoid disclosing these activities,” wrote Skorup.