The experimental method is the type of research that can tell us about causes and effects. It is different from descriptive studies in that key aspects of an experiment—participants, variables, and study implementation—are tightly controlled. An experiment typically includes at least two groups—an experimental group and a control group. This allows the researcher to isolate the effects of manipulating a single variable, called the independent variable.
When is it important to use the experimental method? Imagine you want to know if laws that ban texting while driving are worthwhile. Does texting really cause more accidents? Perhaps texting is merely correlated with higher accident rates in certain populations, such as college students, because college students are both more likely to text and more likely to have accidents. In order to find out, you have to perform an experiment.