Springuel Thompson Wittmann correcting a past paper

R. Padraic Springuel, Michael C. Wittmann, and John R. Thompson
Erratum: Applying clustering to statistical analysis of student reasoning about two-dimensional kinematics [Phys Rev. ST Phys. Educ. Res. 3, 020107 (2007)]

In our paper reported previously in this journal, we explored how cluster analysis, a method from data mining used to find natural groupings in data, could be used to categorize the responses given by students on a free-response question about acceleration in two dimensions. In the process of preparing to expand on that work, however, we discovered that our analysis was both incorrect and incomplete. We were incorrect in that we used default settings in our software package and thereby misidentified the distance measure used. We have since determined that this distance was not appropriate for our data coding. Furthermore, we were incomplete in that we were not sufficiently rigorous in our definition of groups of student responses. We have corrected both of these issues.

This is an erratum related to (and nearly longer than!) the paper found here.