Question

What do you think is the most crucial difference between experimental and non-experimental research regarding variables and validity?

? Please provide an example of the approach you're most attached to (perhaps discuss how might you explore your topic of interest using one of the approaches)?

Answer 1

An experimental research is a study conducted in a laboratory, to test a hypothesis and find out the cause and effect relationship between two variables. In an experimental research, it is possible to ethically manipulate the independent variable (IV), post random assignment of subjects to different levels or conditions of the IV.  An experimental research involves one set of participants called the 'experimental group or the manipulated group'. The other set of participants is called the 'placebo group or inert condition or non-manipulated group'. An experiment conducted in a laboratory, can help a researcher in obtaining high degree of control, precision and reliability.

On the other hand, a non-experimental research can be defined as a study in which it is not possible to establish an actual cause and effect relationship between two variables or manipulate the independent variable or the concerned participants. Such an experiment depends on interpretation, observation and interactions, often taking place in real life setting, to draw a conclusion via correlations, surveys and case studies. A non-experimental research has a high degree of external validity. Thus, the results of a non-experimental research can be generalized to the larger population.

The most crucial difference between experimental and non-experimental research is that in experimenatal research it is possible to ethically manipulate the independent variable (IV), post random assignment of subjects to different levels or conditions of the IV, and find out the cause and effect relationship between two variables, that is, the independent variable and the dependent variable (DV). Whereas in case of non-experimental research, it is not possible to establish an actual cause and effect relationship between two variables or manipulate the independent variable or the concerned participants. Experimental research has the highest internal validity (or the degree to which an experimental design is supportive of the obtained results and the drawn conclusion). This is due to directionality and third variable problems tackled in experimental researches via manipulation, control of confounding variables and random assignmen of subjects to different levels or conditions of IV. Comparatively, non-experimental researches, like correlational and quasi-experimental researches have lower internal validity.

The approach to which i m most attached to is the non experimental research. For example, if i want to study a non-causal relationship between two variables, that is, verbal intelligence and mathematical intelligence, i would have to find the correlation between the variables in a non-experimental research. I will select subjects from different age groups, and will give them tests to complete on verbal intelligence and mathematical intelligence. I will thereby obtain the correlation following the appropriate formula, and can ultimately draw a conclusion.