Turning points, or life events that trigger dramatic and sustained changes in behavior, are a central focus of life course criminology. Most empirical work in this domain focuses on positive turning points that decrease offending and promote desistance (e.g., marriage, employment, military service), yet there is good reason to suspect that offenders may also encounter negative turning points, which amplify rather than reduce offending. This possibility is worthy of consideration given that at least one potential negative turning point – imprisonment – is experienced by millions of offenders. This dissertation integrates the studies of imprisonment and the life course by critically assessing the joint experience of prison and parole (imprisonment) as a turning point in the criminal career, and unpacking heterogeneity in the extent to which imprisonment serves as either a positive or negative turning point. Using criminal records of adults released from Pennsylvania prisons, this work employs a dual trajectory model to assess whether, and to what degree, imprisonment is associated with a disruption in one’s offending pathway. This research also considers the life course principles of cumulative disadvantage and timing by assessing whether imprisonment functions as a different type of turning point for inmates of varying prison histories and ages.

The results indicate that imprisonment may serve as a turning point in the criminal career. Evidence of discontinuity in pre- and post-prison criminal trajectories was observed in 49.03% of the full sample, 44.78% of first time prisoners, 75.48% of repeat prisoners. First-time imprisonment almost universally served as a positive turning point, while over one-third of repeat prisoners exhibited evidence of a negative turning point. Additionally, the number of prior prison terms significantly increased the odds of observing a negative turning point relative to a positive turning point or no turning point, suggesting that the criminogenic influence of imprisonment accumulates over time. The timing of imprisonment also matters. Older inmates were more likely to demonstrate discontinuity in offending consistent with a positive turning point, whereas younger inmates were more likely to exhibit evidence of a negative turning point. The theoretical and policy implications of these findings are discussed.