Читать книгу The Research Experience - Ann Sloan Devlin - Страница 120

Correlational research approaches can be divided into two general categories: correlational and quasi-experimental. What the two approaches have in common is that only correlational relationships are involved; that is, no causality can be inferred. What is typically called a correlational approach involves questions about a randomly selected sample as a whole in which two or more variables are measured (Category 1 from Figure 2.1); what is called a quasi-experimental approach typically involves questions about differences between preexisting groups (Categories 2 and 4 from Figure 2.1).

Although there are groups in quasi-experimental designs, they have not been randomly assigned. Quasi means “resembling.” Even though a quasi-experimental design mirrors a true experimental approach in some aspects (e.g., asking questions about group differences), it does not include the critical aspect of random assignment to condition and the groupings preexist (e.g., gender) or can be formed from preexisting situations (e.g., dividing students into those who own cars vs. those who do not based on responses to a questionnaire). Examples of such preexisting groups in quasi-experimental research are gender, class year, marital status, athlete status, coffee drinker or not, or almost anything where the characteristic in question preexisted or was naturally formed.

True experimental approach: Research approach in which one or more variables are manipulated and participants are randomly assigned to condition.

Random assignment: When participants are randomly assigned to the conditions of the study.