The Difference between Descriptive, Correlational, and Experimental
Studies
Descriptive Research – use systematic observation to describe a specific behavior. Descriptive researchers create very detailed records and observe many subjects. Descriptive research cannot make predictions or determine causality. It simply identifies behaviors and describes the behavior and the participants.
Correlational Research – determine whether a relationship or association exists between two or more variables, but cannot determine if one variable causes another. In correlational research, the researchers do not manipulate any of the variables or put the participants into groups. Although correlational research cannot determine causality, it is useful for predicting the level of one variable based on knowledge of the other variable.
Experimental Research – In an
experiment, one variable is intentionally manipulated by the researchers. The
participants are put into groups through random assignment. Random assignment
is assigning participants in an experiment to groups in a way that each
participant has an equal chance to be in any of the groups. By using random
assignment, researchers ensure that each group should be alike on any
dimension, and therefore, each group is equivalent to the others before the
manipulated variable is introduced.
Most importantly, experimental
research is the only kind of research that can determine causality. In other
words, it can show that variable A causes variable B. It rules out the
possibility of third variables, allowing researchers to make causal claims.