We report in this paper three methodologies used to identify students' understanding levels when different kinds of research have been made. Systems of categories were built to analyze students' responses; these students were at different grades in High School. Our systems were elaborated under three perspectives: SOLO Taxonomy (BIGGS and COLLIS, 1982), Dynamic Skills Theory (FISCHER, 1980, 2006), and teacher's' views for evaluation. Although we reported two investigations, this paper aims to present three methods of qualitative analysis and to elicit criteria and procedures used to build the systems. We believe this kind of methodological issues must be discussed in educational research for improving methods, techniques and investigation parameters.
Methodology; science teaching; learning.