ABSTRACT
Measurement is the process of moving from theoretical definitions of concepts to numerical representations of those concepts as variables. This process is called operationalization. The measurement process involves identifying the appropriate content of interest and designing the appropriate classification system for that content. The classification system develops definitions of variables and categories for the variables. These variable categories must be translated into numbers, which requires the selection of appropriate levels of measurement, a system for classifying content, and rules for applying numbers to the content. This process is governed by coding instructions that maximize the validity and reliability of the measurements of the content concepts of interest. The instructions should allow a different coder to replicate the measurements. Together, the classification system and instructions are called the protocol. Such measurements are then statistically analyzed to address study hypotheses or research questions. Almost always, such analyses are performed by statistical packages on computers.
