Voting by mail led to massive increases in youth and minority turnout in this California county

Having more people vote by mail could lead to dramatic rises in youth and minority turnout—at least if the results from this month’s elections in one California county are any indication.

San Mateo County in Silicon Valley saw huge increases in turnout rates among young people, Latinos and Asians after implementing a vote-by-mail pilot program, according to an analysis reported by the San Jose Mercury News today.

The county sent every eligible voter a mail-in ballot, the kind of ballot that is typically sent only to people who register to vote absentee. In the weeks leading up to the Nov. 3 election day, several polling stations also allowed people to vote in-person when they wanted.

As it turned out, 97% of voters voted by mail and the overall turnout increased by 16% over the last comparable local elections in 2013, according to the News.

Spikes in turnout among young people, Asians, and Latinos were seen in all eight cities with competitive races. Youth turnout rates went up by as much as 160% in some cities, while Asian and Latino turnout increased by up to 96%. All three groups typically have lower turnout rates.

While the cost of the election has not been released, voting by mail is typically significantly cheaper than traditional elections, owing to reduced costs of setting up polling stations. San Mateo did prepay for postage for all the mail-in ballots, however.

The vote-by-mail pilot program will be put on hold for the 2016 presidential election, but will be used again in local elections in 2017 and 2018. If the program continues to rack up turnout increases like those seen this month, the legislature could decide to expand it statewide.

Oregon, Washington, and Colorado already have some form of vote-by-mail systems.

Voting by mail is far from the only election innovation gaining steam around the country. In Maine, a referendum was approved last week that will ask voters next year whether they want a voting system in which they’d rank multiple candidates. It would be the first state to do so.