Disadvantages:
- stimulates the social defence mechanism of the subject;
- the presence of the counsellor modifies the situation to be observed; some
changes are possible in the behaviour of subjects (some counsellors can have
a tonic effect on subjects, while others can intimidate, depress, inhibit); - the counsellor has little control over external variables that can affect the
observation data; - the data collected through observation are difficult to quantify;
- observation is limited to individuals or small samples of subjects;
- the counsellor’s attention can be oriented selectively towards certain
expectations, beliefs, theories, etc., that can affect the objectivity of
observation and based on these choices it is possible to induce the effect of
(self) confirmation; - the difficulty to take notes and observe at the same time leads to recording
the results of observation after a while, occasionally inexact; - aspects related to observation data assessment yield certain categories of
errors (Piaget):
“centring error” – the aspects observed tend to be overestimated in
relation to other aspects,
“contrast error” – the counsellor focuses on the minimum differences
noticed between various aspects, and exaggerates them,
“assimilation error” – the counsellor focuses on the similarities
between various aspects, rather than on the differences,
“the anchor effect” – although the counsellor believes to be evaluating
a singular aspect, the effects of previous observations influence
him/her in the current assessment,
“the halo effect” – the counsellor appreciating certain aspects in a
subject will be influenced in the same way when evaluating other
dimensions (for instance, a pleasant-looking person will influence the
observer when his/her personality is evaluated).