Five Types of Research Studies

Reading and interpreting research can be a difficult task, especially if you don’t have a background in science. The nature of science and scientific examination is built on defining conditions and standards, using specific measures, applying consistent procedures, and observing objectively. In other words, it is predicated on order. Understanding this order—the science model—doesn’t require special expertise, and having a basic grasp of it before you get started reading research will simplify the task. This section introduces you to some key terminology and describes the study framework in which research is conducted.

Single Subject Research

A single case study looks at a single subject (ex. child with ASD) or a single case (ex. classroom for students with ASD).

Correlational Research

Correlational research looks for relationships between two or more variables or things that naturally occur in the same environment.

Longitudinal Studies

Longitudinal studies can give us information about how people develop or change over time.

Experimental Studies

Experimental studies are used to directly study cause and effect.

 

Clinical Trial Studies

Clinical trial studies are a type of randomized experimental study and are most likely to be conducted in medical or other clinical settings. 

A single case study looks at a single subject (ex. a child with autism) or a single case, (ex. a classroom for children with autism).

research-search-resources-information-graphic-iconSingle subject studies are typically used in research in therapeutic settings where there is a one-on-one relationship. Many studies with children with autism – particularly those looking at interventions based upon applied behavior analysis – use a single subject design or, more specifically, a “single subject experimental design.”

The advantages include the ability to control variables which may more clearly identify cause and effect and a substantial amount of information can be gathered about one person or one case.

The disadvantage is the small sample size—information relative to one person or group may not generalize to people or groups in other cases, situations, or settings.

Correlational research looks for relationships between two or more variables or things that naturally occur in the same environment.

network-share-connected-graphic-iconThey do not determine anything about cause and effect, i.e., correlation does not mean causation.

The advantage is that a lot of information can be collected about a large number of people at one point in time.

The disadvantage is that the effect of factors outside of the study that might influence the research cannot be controlled.

Longitudinal studies can give us information about how people develop over time.

people-person-graphic-iconThese types of studies follow one group of people (referred to as a cohort) across time, measuring the same behavior multiple times.

The advantage is that longitudinal studies allow researchers to pinpoint times during development when changes occur.

Disadvantages include the long length of time to complete, the expensive cost, and the difficulty in retaining all participants across the life of the study.

Experimental studies are used to directly study cause and effect.

book-magnifying-glass-research-search-graphic-iconExperiments are controlled so that one variable is manipulated by the researcher to determine its effect on other variables. Research using this method entails two groupings of randomly selected subjects, an experimental group (those who receive the intervention being tested) and a control group—ideally an identical sample to the experimental group that completes all the steps, except the intervention. Therefore, if the study is well controlled, the differences between the experimental and control groups at the end of the study will be due to the intervention.

The advantage is that it allows researchers to more precisely examine cause and effect relationships.

The disadvantage is that the results do not always easily generalize to the real world, i.e. what occurs in a controlled environment may differ from what might occur in a real-life setting.

Clinical trial studies are a type of randomized experimental study and are most likely to be conducted in medical or other clinical settings.

education-teacher-student-support-classroom-education-graphic-iconSimilar to experimental studies, clinical trial studies employ an experimental/control group protocol, in which subjects are randomly assigned to receive the experimental treatment (for example, a medication to treat autism symptoms) or a placebo (a sugar pill).

The advantage is that it can determine the effectiveness of an intervention because the intervention is compared with a placebo or control condition.

The disadvantage is that, as with randomized experimental studies, the results of the study cannot always be generalized to a real-life setting.