Abstract
In the present study, a calculation method was suggested for capture rate, which is an index that stands for the number of kinds of ideas that have been collected in free description data. The DeLury method, a popular calculation method for estimating biological populations, was used to calculate a parameter that estimated the number of kinds of ideas. In addition, by using phantom variables, it was shown that this method can be used in structural equation modeling. Free description data from a university class evaluation coded by the KJ method were used for the analysis, and the capture rate was calculated. The results indicated that this his method revealed more than 80% of the kinds of ideas.
