Using parents as a source of information: There is a widespread belief that, to parents, 'all their geese are swans', and that therefore their report of the child's abilities is likely to be hopelessly exaggerated and quite unreliable. As a result, excessive reliance is placed on the small and often unrepresentative sample of behaviour which can be elicited during a brief assessment session, and the parents' vast store of knowledge about their child is ignored.
Yet only the parents can know whether the child's performance is representative of his/her true abilities or can explain the history of individual items of behaviour — why, for example, a word is used in a particular way or why the child shows an unexpected reaction to a task. Furthermore, the way in which they describe the child and his/her activities gives some insight into the quality of the child's microenvironment.
There are several reasons for the apparent unreliability of developmental information obtained from parents. Firstly, retrospective recall of the times at which milestones were achieved in the past is known to be unreliable. Secondly, where the child's current abilities are concerned, the questions put to the parents are often ambiguous and their replies are not subjected to further critical probing.
Thirdly, it is usually the parent`s interpretation of what they observe rather than their observations which is unreliable; resentment is generated by the failure of doctors and other professionals to recognize this distinction. Agreement must be established first with the parents on what the child can and cannot do, with specific examples being cited. Only then can the significance of the child's abilities be discussed.
Occasionally, parental accounts do seem to substantially over- or underestimate a child's abilities, in comparison with what is seen during assessment. This discrepancy is itself of considerable diagnostic importance, for the parents' lack of understanding may explain many management problems and might be a contributing cause in some developmental disorders. We have seen a small number of parents whose self-deception about their child's abilities is so extreme that it takes on the quality of a delusional system.
A few parents are more consciously manipulative and their description is distorted in order to obtain the opinion they desire. Even more rarely, they may deliberately try to mislead the doctor, perhaps for medicolegal reasons. All of these situations are uncommon, but they must be recognized if the family is to be helped. The parents' view of the child's problem is every bit as important as an 'objective' assessment of the child's development.
