Ceiling Effects and Floor Effects of the Posttraumatic Growth Inventory

The current study investigated the effects of a brief psycho-educational presentation about posttraumatic growth (PTG: positive changes that may occur as a result of psychological struggle with a highly stressful life event) on the self-reported PTG by using the PTG Inventory (PTGI). Few empirical studies have investigated the possible ceiling or floor effects of the PTGI, despite researchers indicating the necessity of longitudinal studies to reveal the PTG processes. This study used a pre-test, brief presentation, and post-test longitudinal design to examine the effects of intervention among adolescents by considering the floor and ceiling effects of the PTGI. Participants, 54 high school students (37 females, 17 males, Mean age = 15.92 years), completed the PTGI at three weeks interval. Results using the Latent Rank Theory approach demonstrated ceiling effects in students who reported a high degree of PTG at Time 1, and floor effects in students with low PTG at Time 1. Presentation effects were not evident even in those who reported a moderate degree of PTG at Time 1. These findings suggest that it is important to be aware of the ceiling/floor effects while measuring changes in PTG perception over time and that explaining the phenomenon of PTG is not likely to be enough to affect the PTG perceptions.