The Index of Learning Styles is an on-line survey instrument used to assess preferences on four dimensions (active/reflective, sensing/intuitive, visual/verbal, and sequential/global) of a learning style model formulated by Richard M. Felder and Linda K. Silverman. The instrument was developed and validated by Richard M. Felder and Barbara A. Soloman. Users answer 44 a-b questions and submit the survey, and their four preferences are reported back to them immediately to be copied or printed out. The results are not stored: when the report window is closed, the results are irretrievably lost.

ILS users should be aware of an important point. The survey results provide an indication of the respondent's learning preferences and an even better indication of the preference distribution of a group of respondents (such as students in a class), but they should not be over-interpreted. A student's learning style profile provides indications of possible strengths and tendencies or habits that might lead to difficulty in academic settings. It does not reflect a student's suitability or unsuitability for a particular subject, discipline, or profession: students with every preference have succeeded brilliantly in every field. Using preferences as bases for curriculum or career counseling can be seriously misleading, and can be harmful if the counseling motivates students to make major changes in their career goals.