The Problems of Interest Group Ratings

In the course of my political research, I have frequently used votes counted by ideological interest groups to get a handle on what is regarded in history and now as liberal and conservative. The most useful ones I have found are Americans for Constitutional Action (conservative, now defunct), American Conservative Union, and Americans for Democratic Action (liberal). Although all these groups are useful, I have found none of the interest group ratings completely satisfactory in grading ideology for several reasons. These are:

  1. They influence phenomena as much as they report it. They are designed to push legislators. If there are two votes on the same subject, interest groups will pick the one in which their position lost or the margins were closest in victory. Example: confirmations of Janice Rogers Brown and William Pryor Jr. in 2005. ADA selected the former and ACU selected the latter. Both were controversial conservative judges Bush was trying to confirm for federal appellate courts. Republicans were unanimous in voting for Brown on June 8 and three dissented on Pryor on June 9, thus ADA chose the Brown vote to portray the Republicans as more right-wing on judicial nominations while ACU chose the Pryor vote to highlight the disloyalty of three Republicans. Votes can be selected for the most extreme positions to penalize party moderates and reduce the difference that is seen between them and staunch believers on the other side.
  2. Sometimes interest groups will highlight pet causes, include votes of questionable ideology, and dock members for behavior outside of votes. ACU, for instance, chose the First Step Act as one of their votes in both Houses despite dissent coming only from a small group of conservative Republicans. This vote does not indicate conservative ideology yet they included it because they participated in its creation. For an example of docking behavior outside of votes, ADA counts failures to vote against senators and representatives. It sure is news to conservatives that failure to vote reflects their position! ACU isn’t innocent here either, as in 2016 they triple-counted statements on the nomination of Merrick Garland. Garland never came to a Senate vote, but the ACU managed to count public statements of wanting to hold a vote on him against all Democrats and a few Republicans, and credited Republicans who went along with McConnell blocking a vote on him.
  3. Conservative ratings don’t tend to do well in determining ideological differences between Democrats and vice-versa. The most egregious examples of this include ADA scoring Tea Party/Freedom Caucus people higher on liberalism than their more moderate, establishment counterparts. For instance, Andy Biggs scored a 25% and Justin Amash a 40% in 2018, while moderate Susan Collins scored a 20%. Also, ACU’s 2017 Senate ratings had over forty Democrats scoring zeroes while only one, Joe Manchin, voted more than once for the conservative position, and he scored an 8%.

Image result for American Conservative Union


Image result for Americans for Democratic Action


These ratings organizations serve as much to ideologically police and lobby as they do to observe and report. Indeed, this phenomenon was observed by researcher Emily J. Charnock in her journal article, “More Than a Score: Interest Group Ratings and Polarized Politics”, when she states that “ADA and ACA scores have been heavily utilized in political science as proxies for liberalism and conservatism and used to demonstrate the growing polarization of the congressional parties. Archival evidence suggests, however, that those scores were intended to create the very phenomenon they have been used to measure. They were deeply political rather than objective metrics, which the ADA and ACA used to guide their electoral activities in accordance with an increasingly partisan strategic plan”. This is one of the reasons I am creating Mike’s Conservative Index. This index does not intend to police or lobby, rather observe and report. Indeed, I include votes back to 1861 and there’s no point to lobbying the past now is there? DW-Nominate’s first dimension tends to do a good job of determining most right-wing members of Congress but it doesn’t do so well on the left, especially in periods of ideological flux and I use the figures who scored the highest on the first dimension to determine what good conservative scores ought to be. My goal is to rectify the issues surrounding interest groups and provide a system that is accessible, so instead of scores like 0.382, I assign a solid percent based on key votes. I confess key votes are a necessary evil of the process, and this is one way my system could be critiqued compared to first dimension DW-Nominate. I also admit that after 1946 I use interest group ratings as a guide for votes, but I will often mix ACA (Americans for Constitutional Action), ACU, and ADA counted votes I find most appropriate given the methodology and rules I have employed. I am certain that my scores will not be pleasing for either the left or right for differing reasons. I am sure, for instance, that many abolitionists being conservative and many people who supported the retention of slavery being liberal will raise hell with the contemporary left as will my counting of civil rights legislation in the 1960s as against conservatism raise hell with the contemporary right. My goal is not to please, but to get closer to the truth.


Charnock, E.J. (2018). More Than a Score: Interest Group Ratings and Polarized Politics. Studies in American Political Development, 32 (1), 49-78.

Retrieved from

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s