Experimental Research
The Uniqueness of Experimental Research * Experimental research is unique in that it is the only type of research that directly attempts to influence a particular variable, and it is the only type that, when used properly, can really test hypotheses about cause-and-effect relationships. Experimental designs are some of the strongest available for educational researchers to use in determining cause and effect.
Essential Characteristics of Experimental Research * Experiments differ from other types of research in two basic ways ― comparison of treatments and the direct manipulation of one or more independent variables by the researcher.
Randomization
* Random assignment is an important ingredient in the best kinds of experiments. It means that every individual who is participating in the experiment has an equal chance of being assigned to any of the experimental or control conditions that are being compared.
Control of Extraneous Variables * The researcher in an experimental study has an opportunity to exercise far more control than in most other forms of research. * Some of the most common ways to control for the possibility of differential subject characteristics (in the various groups being compared) are randomization, holding certain variables constant, building the variable into the design, matching, using subjects as their own controls, and using analysis of the covariance.
Weak Experimental Designs * The essential ingredient of a true experiment is random assignment of subjects to treatment groups. * In a one-shot case study, a single group is exposed to a treatment or event, and its effects assessed. * In the one-group pretest-posttest design, a single group is measured or observed both before and after exposure to a treatment. * In the static-group comparison design, two intact groups receive different treatments.
True Experimental Designs * Several stronger designs that are more commonly used are true
Essential Characteristics of Experimental Research * Experiments differ from other types of research in two basic ways ― comparison of treatments and the direct manipulation of one or more independent variables by the researcher.
Randomization
* Random assignment is an important ingredient in the best kinds of experiments. It means that every individual who is participating in the experiment has an equal chance of being assigned to any of the experimental or control conditions that are being compared.
Control of Extraneous Variables * The researcher in an experimental study has an opportunity to exercise far more control than in most other forms of research. * Some of the most common ways to control for the possibility of differential subject characteristics (in the various groups being compared) are randomization, holding certain variables constant, building the variable into the design, matching, using subjects as their own controls, and using analysis of the covariance.
Weak Experimental Designs * The essential ingredient of a true experiment is random assignment of subjects to treatment groups. * In a one-shot case study, a single group is exposed to a treatment or event, and its effects assessed. * In the one-group pretest-posttest design, a single group is measured or observed both before and after exposure to a treatment. * In the static-group comparison design, two intact groups receive different treatments.
True Experimental Designs * Several stronger designs that are more commonly used are true