Background: This study aims at characterizing the extent of correlation of treatment response (TR) obtained in various observation settings (home, school, clinic) by different observers (parents, teachers, clinicians).

Methods: Children with attention deficit hyperactivity disorder (ADHD) underwent a 2-week double-blind, randomized, cross-over clinical trial with methylphenidate and placebo, and various measures were obtained during the 2 weeks. Interrelationships of TR were examined using Pearson’s correlation coefficients.

Results: The study included 526 children (420 male, 106 female) with ADHD. TR between different observers shows a variable correlation between parents and teachers. No correlation is seen between parents/teacher evaluation of TR and laboratory-based measures (Continuous Performance Task; Restricted Academic Situation Scale).