Survey or questionnaire – what's the difference? In short: the survey is the whole project, the questionnaire is the tool with the questions. We show you clearly how the two connect, when to use which term and what to watch out for in practice.
An absolute scale counts in units that cannot be converted into anything else, because a headcount stays a headcount. We show you how to recognize it and what you may calculate.
Zero dollars means no income, but zero degrees Fahrenheit does not mean no heat. That one difference decides whether you may say “twice as much” about your data.
An interval scale has equal gaps but no true starting point, which is what makes GPA such an awkward case. We show you what you may calculate and where rating scales sit.
Cardinal scale and metric scale mean the same thing. In English statistics that is the interval and ratio scales. Includes the four-question test and what you can calculate.
How to spot an ordinal scale in your questionnaire: the two conditions behind a rank order, the numbers that hold up and the tests that go with them.
A nominal scale sorts answers into categories without ranking them. We show you US examples, the calculations you are allowed to run and how it differs from an ordinal scale.
We show you which types of rating scale exist, how many steps yours needs, how to word them and which statistic you are allowed to report at the end.
Objectivity (= intersubjective comparability) means that knowledge gained must be verifiable and comprehensible independent of researchers' subjective attitudes.