In the Spring issue of ADHD in practice, the potential limitations of subjective information forming the basis of a diagnosis of attention deficit hyperactivity disorder (ADHD) and the objective measures that are available were reviewed, reflecting on their place in clinical practice. If objectivity can be achieved in the diagnostic process, patient care is less likely to be influenced by potential biases and personal opinions of parents, teachers and clinicians. Unfortunately, there are limited data on the diagnostic accuracy of these objective measures, particularly on the differentiation of children with ADHD from healthy controls and other psychiatric patients. The value of these measures lies in their ability to add to the current diagnostic process by providing objective information as a component of a broader assessment process.