The BIS-11 (Patton et al., 1995) is the most up to date and psychometrically sound version of the Barratt Impulsiveness Scale.  Earlier versions should not be used unless they are part of a longitudinal study that began prior to the publication of the BIS-11.  During the development of the BIS-11 an intermediate version of the scale designated in the literature as the BIS-11A (Barratt, 1994) was distributed to several labs for review.  The BIS-11A resulted from an analysis of BIS-10 data during the early development phase of version 11.  Unfortunately, this “working” version of the scale has been more widely disseminated than was ever intended or anticipated.

      Dr. Marijn Lijffijt has developed a procedure by which BIS-11A scores can be prorated to BIS-11 scores.  The reliability of this procedure is questionable but it is a reasonable way to deal with BIS-11A data.  Six items originally present on the BIS-11A are no longer present on the BIS-11 (and vise versa), so the number of items on the BIS-11A is actually 24 instead of 30.  The consequence is that the scores have to be divided by the number of items and multiplied depending on the scale that you are interested in to be consistent with the BIS-11.  If you are interested in trying this procedure please download the attached material.  Please contact Marijn Lijffijt, Ph.D. (Marijn.Lijffijt@uth.tmc.edu) if you have questions related to the prorating procedure.

BIS-11A Prorating

References

      Barratt, E.S.  (1994).  Impulsiveness and Aggression.  In Monahan, J. and H. J. Steadman (Eds.), Violence and Mental Disorder: Developments in Risk Assessment (pp. 61-79).  University of Chicago Press, Chicago, IL.

Patton, J.H., Stanford, M.S. and Barratt, E.S.  (1995).  Factor structure of the Barratt Impulsiveness Scale.  Journal of Clinical Psychology, 51, 768-774.