The definition of research design
A research design is a plan, structure and strategy of investigation so conceived as to obtain answers to research question or problems. The plan is the complete scheme or program of the research. In concludes an outline of what the investigator will do from writing the hypotheses and their operational implications to the final analysis of data (Kerlinger 1986: 279).
The functions of a research design
There are two main functions of a research design. The first relates to the identification and / or development of procedures and logistical arrangements required to undertake a study, and second emphasizes the importance of quality in these procedures to ensure their validity, objectivity and accuracy.
There are two methods used to ensure that extraneous variables have a similar effect on control and experimental groups and two methods for eliminating extraneous variables. First of all, ensure that extraneous variables have a similar impact on control and experimental groups. In addition, it is divided to two methods ensure that the control and experimental groups are comparable to one another:
- Randomization is ensures that the two groups are comparable with respect to the variable(s).
- Matching is another way of ensuring that the two groups are comparable so that the effect of extraneous variables will be the same in both groups.
Secondly, eliminate extraneous variable (s). Sometimes it is possible to eliminate the extraneous variable, or to build it into the study design and it is divided to two methods used to achieve.
- Build the affecting variable into the design of the study is to explain concepts that impact of maternal health services per se.
- Eliminate the variable is to study the impact of a health education program on the attitudes towards and beliefs about the causation and treatment of a certain illness among Europeans and Aboriginal people living in a particular community.