Non-experimental research designs is a type of study that is essentially uncontrolled. The research has little to no ability to influence the variables at work, and therefore the research cannot be considered a controlled experiment. There are several types of non-experimental research designs, including correlational, descriptive and historical. Different Types of Non-Experimental Research

The different types of non-experimental research are bound by the fact that in all cases, the researcher has no ability to control the variables. This contrasts with research where the researcher does control the variables in order to test the influence of one or more variables on the outcomes. Non-experimental research also implies that there are a wider range of outcomes than might be tested for in experimental research, where there is typically a narrow null hypothesis and any results not confirming that will result in a rejection of the null hypothesis.

But the different types of non-experimental research are otherwise quite a bit different from each other, as the antelope and the whale are both in the mammal kingdom but otherwise quite distinct species. Correlational research is the most similar to experimental research, where the researcher is looking for correlations between the variables. The difference, however, is that the researcher has no control over those variables,...

A good example would be to examine the correlation between weather and some outcome -- say the success of the corn crop. The researcher cannot control the key dependent variable, the weather, but still wants to establish whether there is a correlation between warmer weather and sweeter corn (or whatever). The researcher takes care to measure the two variables, but cannot control either, and is simply seeking evidence of correlation.
Descriptive research seeks to describe what is happening. This form of non-experimental research may involve a correlation, perhaps at a starting point, but it might not. Descriptive research, as the name implies, seeks to describe what is happening. An example might be a research project to determine what happens to ex-cons with addiction problems when they return to the community in a halfway house. You could run that as a correlational study, or you could simply describe a set of anecdotes and try to draw some conclusions about the effectiveness of the halfway house program from there. Such descriptive studies could be compared with other similar studies to increase knowledge about the subject matter.

Historical studies focus on gather information from the past and analyzing it. Again, this could be correlational in nature, or it could be descriptive. The difference is that in a historical…