Fig. 1

Reduction Approaches: Items and overlap of the three SFI-10 reduction methods and Pearson’s r correlation with: original SFI-25 (*n = 505, **n = 1433); and ^# = FRI (n = 343). Preferred SFI-10 was Concept version with the highest r value. Concept = qualitative concept-retention method; Factorial = factor analysis method; Rasch = Rasch analysis method. (Only two items were shared in all three methods. Concept shared the most items, then Factorial, then Rasch)