Bipartisanship is hard to come by in this divided and divisive U.S. Congress, and it’s perhaps even more scarcely rewarded. American voters consistently back ideological purity over deal-making, and members’ behavior often follows suit.

So perhaps it’s no surprise that two of the Senate’s more successful presidential candidates—Ted Cruz and Bernie Sanders—are among the chamber’s most partisan: not only in the last year, according to a new ranking, but throughout their tenures in the Senate. Cruz and Sanders have built their brands on translating conviction to public policy, and that’s why their supporters love them. The Washington-busting they’ve promised America won’t come from moving to the middle, and they won’t let any kumbaya aspirations of bipartisanship get in their way.

It’s worth noting that’s not what the creators of the Bipartisan Index would hope Cruz and Sanders glean from their analysis, which evaluates senators’ sponsorship of legislation: how often members can “attract” opposing-party co-sponsors for their bills, and how often they co-sponsor opposing-party legislation themselves. The index’s creators would, in fact, hope for the opposite: that the senators take a good, long look at their performances and consider reaching across the aisle for the sake of good governance.

“[W]e do not believe that it is wrong for members to have partisan bills in their portfolio of co-sponsorships,” writes the former Indiana Senator Richard Lugar, whose eponymous Lugar Center co-produces the rankings, in an online explanation. He goes on: “Nor do we believe that all bipartisan bills are wisely written and considered. However, a consistently low score on this index will be a very strong indication that a legislator is viewing his or her duties through a partisan lens.” (Elsewhere the creators use even stronger language: A really low score shows “a member is giving little thought to working with the other party when he or she introduces bills and makes co-sponsorship decisions.”)

Lugar’s center, along with Georgetown University’s public policy school, evaluated senators on very specific metrics that neither reveal the full picture of their behavior and congeniality nor discriminate between quality and sub-par bipartisan bills. In Lugar’s words, “What we are measuring in this Index is not so much the quality of legislation but rather the efforts of legislators to broaden the appeal of their sponsored legislation, to entertain a wider range of ideas, and to prioritize governance over posturing.”

But in assigning a numerical value to senators’ records, the rankings support popular notions about senators’ behaviors and personalities. According to the new analysis, which tracked the 114th Congress’s first session, Cruz clocked in at 97th in bipartisanship, or second to last. That score is consistent with his ranking in the last Congress, which ran from early 2013 to late 2014, his first years in office. And a “lifetime” ranking of senators in office between 1993 and 2014 shows Cruz at the very bottom of the pack. Cruz’s numbers in the last couple years seem to dovetail not only with his rigid conservatism, but also with his negative reputation in the Senate.

Sanders’s “lifetime” score of bipartisanship is just a few notches above Cruz, though his independent status in the Senate might otherwise have lead some to assume he readily finds common ground with Republicans. According to the index, Sanders—who caucuses with the Democrats and has been in the Senate since 2007—has infrequently found it. (Perhaps because his far-left-leaning policies can inspire cries of “socialist!” from those who disagree.) Unlike Cruz, Sanders’s scores in recent years have changed. In the 113th, he clocked in at 90th place. But in the last year, most of which was spent running for president, Sanders’s ranking dropped: He moved from 90th to 98th, the lowest ranking in the Senate. (Majority Leader Mitch McConnell and Minority Leader Harry Reid aren’t ranked.) It’s not clear why Sanders’s score dropped, though being constantly on the campaign trail might hinder on-the-Hill politicking.

Sanders and Cruz could hypothetically tout their rankings as evidence of their ideological bona fides. Not that they’d tout interpersonal prickliness, but rather the idea that Washington’s work is ineffective and unappealing. Meanwhile, their fellow senator-candidate, Marco Rubio, might not look so kindly at his score. Rubio’s “lifetime” ranking shows him closer to Sanders and Cruz than many other senators—170th out of 227—and his score in the 113th Congress was toward the middle. But last year, he was in the top third of senators. For a candidate like Rubio who’s backed away from past bipartisan work, the score might nevertheless be an unwelcome reminder. (Lindsey Graham, who dropped out of the presidential race, similarly ranked toward the top; another drop-out, Rand Paul, saw a middling score.)

Rubio’s most recent ranking could send a positive message to people who value bipartisanship—just as Sanders’s and Cruz’s lower scores show they aren’t willing to compromise on their ideals. The Lugar Center, after all, encourages members to consider that their ideological opposites “may have good ideas that are deserving of consideration.”­­­ But while evidence of working on those good ideas may play during a general election, it won’t while candidates are proving their ideological mettle to finicky primary voters.