A random sampling of about 101,000 signatures backing the Citizens' Initiative did not have enough valid signatures to immediately head to the November ballot, Registrar Michael Vu confirmed Wednesday.

The Citizens' Initiative would raise taxes on hotel rooms and set aside 100 acres in Mission Valley for public use like parks, an education center and soccer stadium. It would also block any public money from going toward a downtown football stadium and prevent the expansion of the Convention Center along the water front.

Attorney Cory Briggs, who proposed the initiative, said he's confident the measure will be on the November ballot once Vu does a full count of all the signatures. He also took issue with the process being used to validate the initiative.

"It's all because the city is allowing the county to use a penalty system, but the penalty system isn't in the city rules," Briggs said.

The process the county uses for validating signature-driven ballot measures is a complex formula, Vu said. For every one duplicate found in the sample, nearly 1,100 signatures are thrown out of the total.

He said the system is set up like that to prevent signature gatherers from just signing the same name over and over.

Briggs said it's unnecessarily going to cost taxpayers and the city hundreds of thousands of dollars to validate all 66,477 signatures needed to move the measure to the November ballot to go before voters.

Typically, signature drives aim to collect 150 percent more names than required to avoid disqualification due to duplicates or invalid signatures.

"There should be zero duplicates. We paid some of the best people in the industry to remove the duplicates. So, not only is it difficult to believe there are seven duplicates in the entire 100,000 signatures, there shouldn't even be seven duplicates in the 3,300 sample that they 'randomly selected,'" Briggs said.