For most of the past 60 years, the overall experience level of the House has varied within a narrow range: The average length of service was typically between five and six terms, while the median was four or five terms. Over the past few election cycles, though, the share of less-experienced representatives (those in their first through third terms) has risen significantly. In 2009, 147 representatives (33.8% of the entire body) had six years or less of House experience; by 2013 that had risen to 196, or 45%.
The shift has been even more pronounced in the Senate: 54 senators are in their first term, the most since the 97th Congress in 1981. The average length of service has fallen from 14 years in 2009 to less than 10 years in the current Congress; the median length of service in the Senate, six years, is the lowest it’s been since 1981.