Joining patterns across party factions in the US Congress

How does the influence of party factions change over time? This article only begins to tackle this question by looking at which party caucuses newly elected members join. I focus on joining patterns in the current 115th Congress to shed light on which factions are more or less influential in Congress today. I show, first, that almost all incoming members joined an ideological faction when they entered office. Furthermore, the Republican Study Committee attracted the most incoming Republicans; the New Democratic Coalition and the Congressional Progressive Caucus attracted the most incoming Democrats. The moderate factions lagged behind the more conservative and liberal factions in the Republican and Democratic parties, respectively. These joining patterns of newly elected members have important implications for the current and future influence that factions can expect to have in the party and chamber.