Abstract: The invention relates to a method and a system for evaluating reliability of results in a visual reaction test taken by a user. Method steps with following phases are repeated several times: A visual test stimulus with a recognisable value is shown to the user, at a stimulus time-point; The user reports when she recognises the stimulus value, at a reporting time-point; A variable and relatively short delay time is inserted between the visual stimuli; Reaction times between the stimulus time-points and the reporting time-points are recorded; Step times are calculated as a sum of the delay time and reaction time for each step. Correlation between step times and delay times or correlation between reaction times and delay times is compared with predefined correlation values for reliability and thereby the level of reliability of the results is determined.