Disadvantages Verbalisations may be biased because they interfere with the basic task, for instance, changing the speed or the execution method. This is mainly the case if the activity necessitates the use of short term memory. Verbal protocols may reflect only the results of cognitive process, rather than the process itself. Thus the depth of knowledge which can be obtained is often limited, and it may be necessary to do additional investigations. Language may be an inadequate descriptive technique for the process being studied.
Many mental processes depend on visual, auditory, or mathematical imagery for their execution.
Therefore it may be difficult to verbalise such events. Another disadvantage is that it is timeconsuming to analyse audio and video tapes afterwards. This method is used to investigate user procedures that are not well documented.