make direct comparisons between studies that have
employed different instruments.
QoL is seen primarily as a patient-reported outcome [48,
79] with a key distinction being between independent
assessment (e.g., he/she cannot concentrate and this stops
him or her functioning at school and I think he/she should
feel bad about this) and the ‘‘subjective’’ appraisal (I cannot
concentrate, this stops me working at school and I feel badly
about this and it impacts generally on how I feel about
myself). In this respect a child’s own report seems essential
to accurately capture their QoL. However, this is compli-
cated by several issues. Young children (e.g., before the age
of 7 or 8 years of age) may lack the understanding, insight
or communication skills to provide valid self ratings [10].
This may be accentuated in the case of; children with
learning disabilities; those for whom mental health condi-
tions impact on their ability to reflect and report upon their
internal state accurately (e.g., depression); or as is often the
case with ADHD, where the child is unable to concentrate
and apply themselves to answering a questionnaire. In these
cases one may have to rely on a proxy rating by a parent or a
carer. As a consequence measures of QoL designed for
child populations usually have both a child and parent
completed versions. Clearly a proxy rating will allow only a
partial sense of the overall impact of the condition on QoL
which may place important constraints on the validity of
studies that do not directly ask the child about their QoL. It