OTA 235: How to Find Qualitative and Quantitative studies: Quantitative Articles

There are four (4) main types of quantitative designs: descriptive, correlational, quasi-experimental, and experimental.

https://www.wssu.edu/about/offices-and-departments/office-of-sponsored-programs/pre-award/_Files/documents/develop-quantitative.pdf

1. Descriptive researchseeks to describe the current status of an identified variable. These research projects are designed to provide systematic information about a phenomenon.  The researcher does not usually begin with an hypothesis, but is likely to develop one after collecting data.  The analysis and synthesis of the data provide the test of the hypothesis.  Systematic collection of information requires careful selection of the units studied and careful measurement of each variable.

2. Correlational researchattempts to determine the extent of a relationship between two or more variables using statistical data.  In this type of design, relationships between and among a number of facts are sought and interpreted. This type of research will recognize trends and patterns in data, but it does not go so far in its analysis to prove causes for these observed patterns. Cause and effect is not the basis of this type of observational research. The data, relationships, and distributions of variables are studied only. Variables are not manipulated; they are only identified and are studied as they occur in a natural setting. 

*Sometimes correlational research is considered a type of descriptive research, and not as its own type of research, as no variables are manipulated in the study. 

3. Causal-comparative/quasi-experimental researchattempts to establish cause-effect relationships among the variables.  These types of design are very similar to true experiments, but with some key differences.  An independent variable is identified but not manipulated by the experimenter, and effects of the independent variable on the dependent variable are measured. The researcher does not randomly assign groups and must use ones that are naturally formed or pre-existing groups. Identified control groups exposed to the treatment variable are studied and compared to groups who are not. 

When analyses and conclusions are made, determining causes must be done carefully, as other variables, both known and unknown, could still affect the outcome.  

4. Experimental research, often called true experimentation, uses the scientific method to establish the cause-effect relationship among a group of variables that make up a study.  The true experiment is often thought of as a laboratory study, but this is not always the case; a laboratory setting has nothing to do with it.  A true experiment is any study where an effort is made to identify and impose control over all other variables except one.  An independent variable is manipulated to determine the effects on the dependent variables.  Subjects are randomly assigned to experimental treatments rather than identified in naturally occurring groups.