Quantitative research is the type of research that collects numerical data. This means that variables are measured quantitatively. The design that enables collection of numerical data are the quantitative research designs. This lesson will discuss quantitative research designs.
A research design is a plan that enables a researcher to determine the methods of sample selection, instruments to use and methods of analyzing data based on whether the approach used is qualitative, quantitative or mixed methods.
There are 3 main quantitative designs: Survey, Ex Post Facto and Experimental. Survey describes the characteristics of a population at a particular time. There are 3 types of survey; Cross sectional survey, Correlational Survey and Longitudinal Survey. Ex Post Facto (or Causal Comparative Research) means ‘After the Fact’. This means that the researcher investigates the causes after the effect has been observed on the dependent variable. However, the researcher is not able to manipulate the independent variable. It is similar to correlational survey in that both establishes relationship. However, correlational establishes relationship between variables in a single group while causal comparative establishes relationship between groups. Experimental design is unique because it establishes causality. This means cause and effect relationship. There are two categories of experimental design: True and Quasi Experimental.
As you go through this lesson, check also lesson 8 on correlation to remind yourself on how correlation is measured and interpreted.