Types of Quantitative Research

Experimental:
Researcher establishes different treatments and then studies their effects.  At least one independent variable is manipulated, other relevant variables are controlled, and the effect on one or more dependent variables is observed.  This type of research leads to the most transparent interpretations.

Corrrelational:
Researcher looks for and describes relationships that may exist in naturally occurring phenomena.  Involves collecting data in order to determine the degree to which a relationship exists between two or more variables.  This type of research can provide information for more accurate predictions.

Causal-Comparative:
Research that attempts to determine the cause for, or the consequences of, existing differences in groups of individuals.  Also known as ex post facto research.  Interpretations are limited since the researcher cannot say whether a particular factor is a cause or result of the observed variable.  Findings are valuable for identifying possible causes of differences between groups.

Survey:
Researcher obtains data to determine specific characteristics of a group.  Also used to determine the current status of the particular population with respect to one or more variables.  

Quantitative Research

Description:

Emphasis on obtaining evidence to support or refute research questions.  Utilizes the scientific method of inquiry (identification & definition of a problem, hypotheses, and testing hypotheses). 

Major Characteristics of Quantitative Research:

1.	Breaking down complex phenomena into parts for analysis 

2.	Research questions or hypotheses

3.	Data in the form of numbers

4.	Instruments may be used to measure data

5.	Design or statistical control for extraneous variables

6.	Random sampling to control for bias

7.	Precise description of procedures

8.	Data are statically analyzed

9.	Statistical summary of results (significant or not significant) according to research questions / hypotheses

10.	Deductive process

Reference
Fraenkel, J. R. & Wallen, N. E. (1993).  How to design and evaluate research
in education (2nd edition).  New York: McGraw-Hill.