A quantitative psychologist is a psychologist specially trained to apply mathematical and statistical concepts to psychological principles. Typically, quantitative psychologists earn a doctoral degree in quantitative psychology and techniques. They can apply this training to research projects in any branch of psychology.
One of the fields a quantitative psychologist might work in is measurement of psychological attributes, such as IQ. Quantitative psychologists can develop tests and other measurement tools used in psychological research or everyday psychological processes. They may also evaluate psychological measurement tools, making sure they are reliable and valid ways of measuring psychological principles.
Research design is another place in which a quantitative psychologist can apply his or her techniques. It is difficult to design reliable research projects, and quantitative psychologists can help develop research methods that get improved results. They may focus on designing the method of data collection, by refining or creating tools such as surveys and tests.
It is also important that a psychological research study is able to clearly show cause and effect. A qualitative psychologist can make sure the design of the study is sound enough to draw conclusions from. A reliable study is also generalizable, meaning a researcher can make inferences about the general population based on results from the people in the study. This is another area where a quantitative psychologist can verify and improve the study.
Quantitative psychologists also are trained to mathematically and statistically analyze psychological data. For example, they may take a result from a clinical trial and use statistics to tell whether or not the result is relevant, or if the results could be due to chance. They may also use mathematical and statistical principles to compare different research methods to see which is better.
Statistics and other mathematical principles can also be applied to psychology to model psychological processes. For example, a quantitative psychologist might use a mathematical principle to model a person’s decision-making process. Computer models are another way quantitative psychologists can model and describe psychological principles.
An American Psychological Association (APA) task force found that although the demand for quantitative psychologists is quite high, there are relatively few doctoral degrees awarded in the field every year. This means the job market for a quantitative psychologist is very good as of the late 2000s. A psychology student must go through rigorous training, including courses in mathematics and statistics, to become a quantitative psychologist. This emphasis on mathematics may be what discourages many students.