Rasch Measurement Model Primers
We use advanced techniques to score the survey, similar to those used by national standardized test makers. Using Rasch analysis, we combine data from a set of questions conceptually related to each other. This technique provides us with one score for the concept while taking into account that some questions are more difficult to agree with than others. For example, teachers were asked to rate the extent to which certain behaviors are a problem at their school in a teacher measure called Disorder and Crime. "Threats of violence toward teachers" is more difficult to endorse than "disorder in hallways" because it likely happens far less often.
Rasch analysis also allows us to account for the difference within questions. For example, it may be easier to go from strongly disagree to disagree than it is to go from agree to strongly agree. Rasch takes those differences into account for every question.
These primers offer more technical details on Rasch analysis: