| Term | Definition |
| Spurious Relationship | A coincidental statistical correlation between two variables, shown to be caused by some third variable. |
| units of analysis | the what or whom being studied. In social science research, the most typical units of analysis are individual people. |
| Social artifact | any product of social beings or their behavior. Can be a unit of analysis. |
| reductionism | a fault of some researchers: a strict limitation (reduction) of the kinds of concepts to be considered relevant to the phenomenon under study. |
| Cross-sectional Study | a study based on observations representing a single point in time. |
| longitudal study | a study design involving data collected at different points in time |
| trend study | a type of longitudinal study in which a given characteristic of some population is monitored over time |
| cohort study | a study in which some specific sub-population, or cohort, is studied over time, although data may be collected from different members in each set of observations |
| panel study | a typ of longitudinal study in which data are collected from the same set of people (the sample or panel) at several points in time. |