The early returns from King County on Tuesday night showed that, so far, about 22,000 fewer people voted on Tim Eyman's Initiative 1033 than voted on Referendum 71.

Opponents of the measure said for weeks they were worried King County voters would have trouble finding the measure on the ballot. The initiative was placed underneath a large diagram, on the left side of the mail-in ballot, that showed people how to vote.

Matt Barreto, a political-science professor and director of the Washington Poll at the University of Washington, said last month he didn't think there would be much confusion. Now he's changing his mind.

"It appears to be the reason" for the drop-off in votes he said, adding that more analysis needs to be done.

Kim van Ekstrom, a spokesperson for King County Elections, said they're pretty sure placement was an issue.

"It's pretty clear to us that ballot placement definitely would have contributed to the degree of undervote that we've seen on it," she said. "We're going to work with what we've learned from this experience to do better on the next one."

Another factor, Barretto said, could be that the R-71 campaign was better organized than opponents of I-1033 and turned out people who just voted for the referendum and skipped Eyman's measure.

In this case, it didn't matter. I-1033 is losing by a large margin in King County and statewide. The initiative would have limited tax-revenue increases for state, city and county governments to the rate of inflation and population growth. Any money collected above the limit would have been used to reduce property taxes.

However, if R-71 had been in the spot where I-1033 appeared, the story could be different, Barretto said, because the R-71 contest is much closer and King County is offsetting the no vote elsewhere in the state.

The Washington Poll at UW is projecting R-71 will be approved by about a 52 to 48 percent vote statewide. The referendum expands the state's domestic-partnership law.