--- - |2 Abstract Why has the probability of going to prison after a felony conviction increased since the early 1980s? Social scientists often try to answer this question through macro‐level research that is aimed at examining correlations between prison admissions and crime rates or sociopolitical characteristics of states. That type of macro‐level inquiry, however, does not allow for a close examination of how characteristics of offenders changed over time, and whether such changes are consequential for understanding trends in the use of imprisonment. In the current study, I take a different approach—one in which case‐level data are observed over a lengthy time span—to investigate why the likelihood of going to prison for a given crime persistently increased for several decades. The results of analyses of more than 350,000 felony cases sentenced in Minnesota during a 33‐year period show that the probability of a defendant receiving a prison sentence increased from 1981 to 2013, as would be expected. The primary reason for the rising probability of imprisonment was the significant increase in the average offender's criminal record, which more than doubled during the observation period. - 'Criminology, Volume 57, Issue 1, Page 157-180, February 2019. '