It's the No. 1 thing advocates ask when they get in to see a lawmaker: Would you please cosponsor our legislation? Organizations and congressional offices point to cosponsorships as evidence that a bill has momentum, and to signal their own effectiveness. But National Journal's strategic-research team found that having a lot of people sign on to a bill doesn't necessarily make the legislation more likely to pass.
NJ's team looked at every bill introduced in the House during the 112th Congress (not counting resolutions), and a scatterplot of the data reveals a definite pattern—dotted swiss. There was a very slight link between bill-passage rate and the number of cosponsors a bill attracted, but it wasn't close to predictive—and wasn't far from nonexistent. Even bills that garnered more than 200 cosponsors had only a 45.8 percent success rate, in a body that requires 218 votes for passage.
Up on the Hill, staffers were only mildly surprised to learn that this was the case. For one thing, they point out, the House isn't passing all that much legislation to begin with these days. And, on a percentage basis, much of what is making it through is legislation of the renaming-a-post-office variety. That kind of bill isn't likely to draw a lot of cosponsors or to require a groundswell of backers to pass. In addition, they say, lawmakers frequently introduce legislation for reasons that have nothing to do with actually legislating. Says one House Republican aide: "A lot of bills are introduced just as messaging points, and there's no intention of getting them passed."