What is one limitation of using observation and interview methods for personality assessment?

Potential contamination of results by the presence of the observer

Observation and interview methods possess the following limitations:

(1) These methods necessitate extensive professional training to gather valuable data, which can be demanding and time-consuming.

(2) The psychologist's maturity is a prerequisite for obtaining reliable data through these techniques.

(3) The mere presence of an observer may compromise the results. As an unfamiliar individual, the observer's presence may influence the behavior of the person being observed, potentially hindering the collection of accurate data.