1. Exploratory research design
This is the most appropriate when there is little or nothing known about a phenomena of study and there is need to gain insight and ideas about a problem e.g. customer surveys to find out customer tastes and preferences.
2. Descriptive research design
This is most appropriate where the researcher is fairly knowledgeable about a key aspect/subject of study but has little knowledge if any regarding their characteristic nature of details; hence a descriptive study helps to generate knowledge about the qualitative and quantitative elements of what is being studied.
3. Causal research design
This is concerned with determining a cause and effect relationships and it involves manipulating one or more variables in order to determine their effects e.g. manipulating price to determine its effect on sales of a company.