(Bloomberg) -- Representative  Jim Jordan of Ohio has been been making progress in his quest for the House speaker’s gavel, with a floor vote expected on Tuesday. But a Bloomberg analysis of his voting history shows that he is out of step with the GOP caucus he wants to lead.

Jordan, a co-founder of the House Freedom Caucus, votes more conservatively than any Republican speaker in at least three decades, according to ideology scores that rank how similarly legislators have voted on an economic liberalism-to-conservatism spectrum. The scores are based on a model known as DW-NOMINATE, which was first developed by two academics at Carnegie-Mellon University more than 30 years ago and is widely used by political scientists.

The measure also places Jordan further from his party’s median score than the last several Republican speakers.

While a lot of other factors are at play — Donald Trump, personal relationships, fundraising prowess, and MAGA politics, to name a few — understanding how Jordan is positioned relative to the House GOP’s voting preferences, and to other potential candidates waiting in the wings, suggests he may have a hard time keeping Republicans united.

To assess this, Bloomberg calculated closeness scores by taking the average distance between Jordan and each of his fellow Republicans on two DW-NOMINATE measures — the primary economic one and a second dimension that captures residual differences in voting records (such as on social and cultural issues) that some political scientists say reveal institutionalist-vs-outsider dynamics.

There’s a debate in political science circles about how these DW-NOMINATE scores are used and interpreted, with some critics arguing that they're a better measure of party loyalty than ideology, but this is a minority opinion within the field, according to Charles Stewart III, a political science professor at the Massachusetts Institute of Technology and director of the MIT Election Data and Science Lab. He pointed out that if the criticism were true, the primary DW-NOMINATE score would line up neatly with so-called “party unity scores,” but it doesn’t.

In terms of how ideologically aligned he is to his fellow Republicans, Jordan is in the 82nd percentile on economic issues — meaning four in five GOP members are closer with their peers, on average. He is in the 69th percentile when looking at other issues.

At the same time, US House Majority Leader Steve Scalise, who withdrew from consideration last week amid strong internal opposition, is around the 20th percentile on both scores.

There are only 32 Republicans less like the House GOP overall than Jordan. Interestingly, the current interim speaker,  Patrick McHenry of North Carolina, is the fourth most closely aligned member on average with his fellow House Republicans. If Jordan fails in his bid, some lawmakers have said that McHenry’s limited powers as interim speaker should be expanded, which would likely require Democratic support.

If elected Jordan wouldn't be the first speaker who's voting history differed from his peers. A similar analysis for House Democrats shows former Speaker Nancy Pelosi was left of roughly three-fourths of her party in the last Congress.

“Party leaders might be more extreme now as a result of the close party balance in the House,” said Barry Burden, a political science professor at the University of Wisconsin-Madison. “The narrow margins for the majority party in recent years empower more strident and extreme factions within the party to demand fidelity to their preferences. It is possible that Pelosi's more liberal position helped her maintain exceptional party discipline even while sometimes managing tenuous majorities.”

Tuesday’s expected floor vote will reveal whether, like Pelosi, Jordan’s whip operation can overcome his party’s deep ideological divisions to deliver the 217 votes he needs to become the next House speaker.

©2023 Bloomberg L.P.