A top pollster to 2012 GOP presidential nominee Mitt Romney said Republicans must include more cellphones, young and Hispanic voters in their surveys to achieve more accurate results, a costly venture.

Veteran GOP pollster Glen Bolger argued that the 20 percent sample of cellphone users was not enough.

“It will increase costs, but as a party we have no choice,” Bolger wrote on his website Monday.

Republican pollsters were criticized this cycle for their surveys, which inaccurately predicted the results of many battleground states. In the wake of Romney’s loss, even the most prominent GOP survey gurus questioned their samples.

Bolger declared that polls must “include more young voters in our samples.” This cycle, Bolger included a sample of 40 percent to 42 percent of voters ages 18-44. The actual share on Election Day was 46 percent, Bolger wrote.

Bolger emphasized the need to poll through Election Day, declaring that “late polling is not just for curiosity’s sake.” He also said Republicans must increase the number of Hispanics in their samples.

“That’s important to get right in 2014, 2016, and beyond,” he wrote. “We have routinely conducted Spanish language interviewing in this cycle and previous cycles, but we need to increase the number of states and districts where it is done as a matter of course. It also affects cost, but the continued growth in the share of the vote that is Hispanic means it is important.”