The Democratic party says a $30m investment in engaging Latino and other minority voters helped it achieve a net gain of 34 House seats and improve on 2014 turnout.

Ben Ray Luján, chairman of the Democratic Congressional Campaign Committee (DCCC), said that compared to the previous midterm election, Latinos increased their participation by 174% in 2018. Pacific Islanders increased their numbers by 218% and African Americans by 157%.

“Latino voters played a pivotal role in taking back the House,” Luján said on a conference call hosted by the Latino Victory Fund, a political action committee. He said the Latino vote was especially consequential in a handful of House races across demographically diverse Sun Belt battlegrounds: Nevada, Arizona, Florida and Texas.

Luján, the first Latino to serve as DCCC chair, attributed high turnout among the Democratic base – which includes Latinos, millennials, African Americans, Asians and women – to the “unprecedented” $30m investment.

“Evidence is clear,” he said. “Early and active and robust outreach to communities of color – in this case, into the Hispanic community – clearly pays off.

“Latinos showed up to the polls because we talked to them, we listened to them, our candidates connected with their personal stories, we knocked on their doors and we reached out to them online.”

Luján said the engagement effort included an investment of at least $21m in Latino candidates and in 17 Spanish-language district-specific ads. His office also launched the first multi-state Spanish-language TV ad, in the last week before the election in the aim of getting out the vote.

The Democrats targeted 111 Republican House districts, 29 of which had at least a 10% Hispanic electorate.

Dan Sena, DCCC executive director, said the polling company Latino Decisions conducted nationwide focus groups to better identify the needs of Latino voters and to tailor a proper message.

As Donald Trump roiled his base with warnings about a migrant caravan and gang violence, Sena said his group honed in on a positive message: trying to create an environment in which Latinos had something to vote for, rather than against.

“We wanted voting to feel good rather than simply what is at stake and kids in cages and Trump,” he said. “So we spent a fair amount of time really studying how to create urgency without making it feel overly heavy and overly sad.”

Sena added that the strength of the Latino vote was no longer a hypothetical.

“The proof is in the pudding,” he said, adding that investing in communities of color was “necessary to the longterm success of the party”.

In 2018, Latinos voted for Democrats by a margin of nearly three to one, according to Matt Barreto, co-founder of Latino Decisions. His polling found that 73% of Latinos voted Democratic while only 23% voted for Republicans.

Barreto said Latinos identified healthcare as the most important issue, followed by immigration. Latino voters said they were “tired of the discussion of immigrants in such a negative and racist” overtones, which Barreto said was how the respondents characterized the commentary from Trump and Republicans.

During the campaign, Trump kept up a drumbeat of warnings about a caravan of “bad thugs” and potential terrorists supposedly intent on invading the US from Mexico. He suggested sending up to 15,000 troops to the border.

Luján highlighted the victory of Antonio Delgado in New York as an example of how a Latino candidate won, he said, by keeping a positive message even when facing racist attacks.

“Antonio did not get distracted by any of that,” Luján said. “What he did was he talked to the American people and the people of the 19th district of New York about the economic challenges that they are facing every day.”

The Hispanic community will have a record level of representation on Capitol Hill, with at least 34 Democrats and eight Republicans in both chambers. One House race featuring a Hispanic candidate has yet to be decided.