Interval data: numbers you collect actual reality, 1:1 correspondence between number and what your measuring, age population-interval data, numbers that the researcher records. You can"t ask someone to respond to this question in numbers, when you measure people"s attitude it"s different, Comprehensive: a good theory should be comprehensive, you should be able to apply it to other findings, and another word for comprehensive is for generalizability-- findings apply beyond one case, Reliability: if you do the study several times and you get consistent results it"s reliable. Validity: the degree to which it measure what it intends to measure, when a variable measures what it intends to measure, Causality is cause and effect relationship among the variables www. notesolution. com. Surveys: most common form of research used by sociologists, When you prepare a questionnaire you need a hypothesis- clear and precise, identify the population (universe), Generalize from the sample to the universe if it"s random.