Chapter 4: Measurement and Units of Analysis

# Key Takeaways

## Key Takeaways

is about consistency.*Reliability in measurement*is about social agreement.*Validity in measurement*means that the experiment actually tests what it seeks to test, while*Internal validity*means that the study is generic to other situations and contexts.*external validity*- A
refers to a grouping of several characteristics.*variable*are those characteristics.*Attributes* has attributes that meet the criteria of exhaustiveness and mutual exclusivity.*Nominal level of measurement*can be rank ordered, though we cannot calculate a mathematical distance between those attributes.*Ordinal level measurement*meets all criteria if the two preceding levels plus the distance between attributes is known to be equal.*Interval level measurement*has attributes that are mutually exclusive and exhaustive, can be rank ordered, have an equal distance between them, and have a true zero point.*Ratio level measurement*is the entity that you wish to be able to say something about at the end of your study, probably what you’d consider to be the main focus of your study. A*Unit of analysis*is the item (or items) that you actually observe, measure, or collect in the course of trying to learn something about your unit of analysis.*unit of observation**An*is one that causes another. It is the variable that is manipulated by the researcher in order to measure the difference in the outcome or the dependent variable.**independent variable***A*is one that is caused by another.**dependent variable***An*may compete with the independent variable in explaining the outcome.**extraneous variable***A*is an alternative factor, to the idea that you might have been expecting respondents to try to answer, that may account for the results you observed in your research.**rival plausible explanation (RPE)**