The findings
What 193 scored members and 12,728 parsed stock trades show. Short version: self-dealing is concentrated in a minority of members, and party explains only a sliver of it.
Every scored member, colored by party
Dem Rep IndEach dot is a member; click one for the receipts. Both colors show up at every level, top to bottom.
Is this a party story? Mostly no, and here's the exact number
We test it instead of asserting it. In the current sample, Republicans' median score is 24 and Democrats' is 18. That gap is statistically real (permutation test, p = < 0.001), so we say so. It's also small: party explains 6.6% of the variation in scores. The other 93% is individual behavior.
Two caveats cut in opposite directions. The 193 members scored so far were picked for balance (100 D, 91 R), not at random, so the gap may move as the rest of Congress is scored. And the scores don't track ideological extremity at all: the correlation between score and distance from the center is 0.05 (p = 0.52). Moderates and hardliners self-deal at about the same rate.
Ideology from Voteview's DW-NOMINATE (first dimension), rescaled 0–100. Correlation with score r = 0.29, 95% bootstrap interval 0.14 to 0.43.
How scores are distributed
Most of Congress clusters low; a minority drives the tail. 2 of 193 score 50 or more.
What drives the score
Average sub-score where data exists. Stock trading produces the highest individual scores.