Three main purposes of research are to describe, explain, and validate findings.
Descriptive research studies use microscopes, surveys, computer models and even standardized testing as observational and measurement tools, depending upon the study.
An example of a correlational study may be helpful. As you well know, as children grow older, they become better readers. In other words, there is a correlation between age and reading ability.
For example, the population date may be gathered from several cities and used to determine the growth of a city or state. The future growth will be calculated using the descriptive research.
Ex post facto, or “after the fact” designs, attempt to identify a natural impetus for specific outcomes without actually manipulating the independent variable. This type of design is often utilized when it is not possible to control the experience, exposure, or influences which may affect participants.
The purpose of experimental or quasi-experimental research is to establish a cause and effect relationship between two variables. The researcher deliberately manipulates a treatment (or independent variable) and measures how it affects the behavior or reaction of subjects (the dependent variable). In order for this research design to be appropriately utilized, the researcher must be able to:
*randomly select subjects,
*randomly assign subjects to intervention and control groups,
*randomly assign treatment to intervention groups, and to
*control the treatment (or independent variable) and any extraneous
References: Leedy, Paul D.; Ormrod, Jeanne Ellis (2012-02-08). Practical Research: Planning and Design (10th Edition) (Page 186). Pearson HE, Inc.. Kindle Edition. Nancy Nelson Knupfer Kansas State University Hilary McLellan McLellan Wyatt Digital