Long-term reliability and stability of behavioral measures among adolescents: The Delay Discounting and Stroop tasks

- Reliability and temporal stability studies among early adolescents were needed.
- Good reliability in Delay discounting and acceptable level in Stroop was found.
- Interference Index by RT is preferable when using longitudinal designs.
- Temporal stability of both tasks among early adolescents yield acceptable values.

Delay Discounting (DD) and the Stroop test are two fundamental tasks for the assessment of impulsivity and inhibitory control, core features of several behavioral disorders. Although the study of reliability and temporal stability is important, only studies with adults and small samples have been carried out. The aim of this study is to assess the one-year reliability and temporal stability of both tasks among adolescents. A total of 1375 adolescents (M = 13.08 years old, SD = 0.51) made up the final sample (53.5% males). The results showed moderate stability and good reliability for both DD (α = 0.90) and Stroop (α = 0.85). Indices based on the reaction times and not the number of errors are recommended when using the Stroop test. These results support the use of both behavioral tasks in longitudinal research among adolescents.