How did we grade Missouri's legislators?

The short answer is "math". The long answer is, well, much longer.

Based on a formula from the Legislative Effectiveness Project, we graded the House and Senate's 2017 session. The formula only measures how successful a lawmaker was at getting his or her sponsored and co-sponsored legislation through the process and into law. It doesn't take into account amendments, filibusters or deal-making that may be part of a legislator's overall accomplishments. Where appropriate for local legislators, we've relied on our political reporters' expertise to note those other factors.

First, we used the OpenStates API to download information about the Missouri Legislature's 2017 session. Next, looking at the House and the Senate separately, we used a formula based on the Legislative Effectiveness Project to calculate an "effectiveness score" for each legislator. This formula took into account the entire chamber's record of bills sponsored and co-sponsored, and how far each bill progressed toward becoming law. We removed appropriations (aka budget) bills from consideration.

For example, Sandy Crawford, a Republican representing House District 129, earned an effectiveness score of 1.13, which is very near to the average (set by the formula at 1.0). This score was the result of 13 sponsored bills, three of which passed the House and one of which was sent to the governor, as well as three co-sponsored bills, of which two were passed by the House and both sent to the governor.

Then we generated a "benchmark score" for each legislator. This looked at his or her party, time in the current seat and number of committee and subcommittee chairmanships held. Those attributes were used, along with the entire body's effectiveness scores, to work out what the average legislator with those characteristics would have been expected to score.

Crawford's benchmark was 1.08 — meaning that by looking at the chamber as a whole, we could expect a Republican representative who's been in the seat for four sessions and holds one committee chairmanship to earn a 1.08.

Looking at the ratio of the effectiveness score to the benchmark score shows how a legislator performed versus how well she could have been expected to perform, with a 1 meaning that she met expectations exactly. Crawford's 1.13 effectiveness score slightly outperformed her benchmark of 1.08. The ratio is 1.04.

Finally, we awarded grades. Scores within .5 standard deviations of the average positive or negative earned a C grade. Between .5 and 1 standard deviations above average earned a B (below average, a D). More than 1 standard deviation above average got an A (below average, an F). Crawford's ratio of 1.04 is almost exactly average, earning a C.

Once again, this formula only takes into account certain factors: the number of bills sponsored and co-sponsored; how far each bill moved through the legislative process; and legislators' party, tenure and number of committee chairmanships. Legislators' accomplishments or factors outside these areas are not reflected in the calculations or ultimate grade.