In web questionnaires which are created in paging design where each question is on a separate page, a progress indicator is an element that should inform the respondent about their current position within the questionnaire. Linear progress indicators are commonly used, and sometimes fast-to-slow progress indicators are used for research purposes. In this paper, we programmed an individually adapted progress indicator which monitors respondents' answers, validates them in real time and gives the respondent an additional motivational impulse (in the form of acceleration) only if necessary. We were interested to see how such a progress indicator affects the response quality and dropout rate of respondents in comparison with linear and fast-to-slow progress indicators. According to the results of this study it appears that individually adapted progress indicators increases a participant's commitment to finish the survey, increases the time devoted to responding and the number of answers given.