Experimental research design involves manipulating one or more independent variables and measuring their effect on one or more dependent variables. Through this approach, researchers can observe and record the impact of the independent variables on the dependent variables over time, enabling them to draw conclusions about the relationship between these variables (Blog, 2021).
For example, consider a study aiming to determine the effect of a new drug on treating dementia. The researcher randomly divides a sample of dementia patients into three groups: the first group receives a high dosage of the drug, the second group receives a low dose, and the third group receives a placebo, such as a sugar pill. The first two groups are experimental groups, while the third group serves as the control group. After administering the drug for a period of time, the researcher compares the improvement in the condition of the experimental groups to that of the control group. If the experimental group shows a significant improvement compared to the control group, it can be concluded that the drug is effective. Furthermore, the researcher can also compare the conditions of the high and low dosage experimental groups to determine if the high dose is more effective than the low dose (Blog, 2021).
On the other hand, non-experimental research design does not involve manipulating or controlling independent variables. Instead, researchers measure variables as they naturally occur without any further manipulation. One type of non-experimental research design is correlational research, which aims to identify relationships between variables. In correlational research, the researcher measures the variables of interest without manipulating them (Blog, 2021).
For instance, imagine a researcher investigating the relationship between the socioeconomic status of students’ families and their academic performance. To conduct this study, the researcher administers a questionnaire to students to determine the average income of their families. The researcher then compares this information with the students’ grade point averages (CGPAs). This non-experimental approach allows the researcher to examine whether there is a positive correlation, negative correlation, or no correlation between these two factors at the end of the study (Blog, 2021).
One key distinction between experimental and non-experimental research designs is the level of control applied to the variables. Experimental research design provides a higher level of control as it allows researchers to manipulate and control independent variables. In the example of the drug study, the researcher has control over the dose administered to each experimental group. By manipulating this variable, the researcher can explore the impact of different doses on the outcome measure. In contrast, non-experimental research design does not involve manipulation or control of independent variables. In the example of the correlational study, the researcher only measures the existing variables of family income and CGPAs (Blog, 2021).
Controlled experimentation allows researchers to minimize the influence of factors other than the one being tested. It ensures that an experiment effectively tests the aspects it claims to examine (Crotty, 2018). In experimental research design, researchers have the ability to control and manipulate variables that might confound the results. This control helps to establish a cause-and-effect relationship between the independent and dependent variables. Conversely, non-experimental research design lacks this level of control, as researchers cannot manipulate variables. They rely on measuring variables as they naturally occur, without making any changes to them (Blog, 2021).
In conclusion, experimental research design involves the manipulation of independent variables to observe their effect on dependent variables, while non-experimental research design measures variables as they naturally occur without manipulation. Experimental research provides a higher level of control by allowing researchers to manipulate variables, while non-experimental research lacks this control. Both approaches have their advantages and limitations, and their suitability depends on the research question and the available resources.