This document discusses the measurement of variables in research. It defines a variable as a measurable characteristic that can take on different values. There are different types of variables, including independent variables, dependent variables, intervening variables, moderator variables, control variables, and extraneous variables. Variables can be measured at nominal, ordinal, interval, or ratio levels. The level of measurement determines what statistical analyses can be used. In conclusion, understanding how variables are defined and measured is important for conducting research.