Unofficial returns showed the measure was defeated Tuesday by an 84 percent to 16 percent margin, The Kansas City Star reported.

The proposed tax would have raised an estimated $40 million a year for 20 years, which proponents said would be used to recruit top scientists to work on research at Children’s Mercy Hospital, St. Luke’s hospitals and The University of Missouri-Kansas City’s four health professional schools. The focus of the research would have been translating research into medical cures and new drugs.

Opponents supported medical research but argued that Jackson County residents shouldn’t have to provide research dollars to the medical institutions.

“I’m in favor of research. This was just a bad way to go about it,” said Springfield lawyer Brad Bradshaw, who spent about $250,000 fighting the proposal.

Supporters, who outspent opponents 4-to-1 during the campaign, said two months of advertising and direct mail from the opposition changed early favorable reaction to the proposed tax.

“In part there was a resistance to taxes,” said Civic Council member Robert Kipp. “In part there was a subterranean, organized opposition of people with other agendas.”

Opponents said voters accepted their argument that the sales tax was not the proper funding mechanism.

“You’re asking Jackson County for the largest and lengthiest tax increase in its history for something (voters) will see no return on,” said Marcus Leach, a consultant and spokesman for Citizens for Responsible Research.