Categorization of Mechanics Problems by Students in Large Introductory   Physics Courses: A Comparison with the Chi, Feltovich, and Glaser Study
  With inspiration from the classic study by Chi, Feltovich, and Glaser [1], we asked introductory physics students in three introductory physics classes to categorize mechanics problems based upon similarity of solutions. To evaluate the effect of problem context on students' ability to categorize, two sets of problems were developed for categorization. Some problems in one of the problem sets that students were asked to categorize included those available from the prior study by Chi et al. Our findings, which contrast from those of Chi et al., suggest that there is a much wider distribution of expertise among introductory students. 
Andrew Mason and Chandralekha Singh
physics.ed-ph