Democrats are thinking hard about how to talk to the American public about the impeachment of Donald Trump, even with the Senate set to vote against removing him this week. There’s still a lot of talking to the public left to do, as the process of electing a new president–or re-electing an old one–began ( rockily ) this week in Iowa. A San Francisco data science firm with a unique way of collecting voter opinion believes it has found the answer to that question.

The firm, Swayable, works for progressive candidates, groups, and causes to test and hone the messaging in their video ads to influence the greatest number of people. It’s one of a new wave of data science startups using tech to get at authentic voter reactions in a world where people shun phone and text surveys.

The company is even careful about how they find people to sample on social media. One of its founders, James Slezak, told me that people who self-select to take surveys on social media often carry torches for particular issues or have axes to grind with specific politicians. Such folks are over-indexed in places like Facebook and Twitter, while mainstream voters are often underrepresented. Swayable aggregates a large, politically and demographically diverse respondent group by offering incentives to app users, usually consisting of free stuff they’d normally pay for in-app.

On the impeachment question, Swayable starts out with the assumption that the subject affects different people in different ways. One person may care very little about the specific charges against the president, but care a lot about Trump’s general fitness for the job. Others might see the president’s Ukraine affair as a single act of wrongdoing, and care only whether it’s impeachable. Democrats have to know how to frame the issue to make it persuasive to the most voters, while making it off-putting to the least number.

Before the Iowa caucuses, Swayable was asked by its Democratic advocacy group client to test Americans’ responses to different ways of talking about the impeachment. The firm agreed to share the substance of the results with Fast Company. (The test videos and identity of its client are confidential.)

Testing the message

Swayable asked people to watch videos that talked about impeachment in three ways:

One video stated matter-of-factly the facts about Trump’s general pattern of corrupt behavior. Rather than talking about the Ukraine, it listed the Trump associates who are in jail or headed for jail, like Paul Manafort and Michael Flynn.

Another discussed the constitutional obligations of the Congress in the impeachment trial. “. . . the question facing lawmakers today is whether the substance of President Trump’s acts constitute high crimes and misdemeanors–what’s your take?” the short video says.

A third talked about the details of the Ukraine scandal, and the details of the accusations against Trump.

The respondents were then asked agree or disagree on a 1-10 scale with three questions relating to the video they watched, such as: “Do you believe that President Trump has committed crimes while in office?” Their answers were then averaged, and that average was compared to the averages of a larger control group of people who had answered the questions but had not seen the video. The comparison showed how much the video had persuaded the respondent.