There are different types of research methodologies which can be divided into three broad categories namely qualitative, quantitative and mixed research. Qualitative research uses descriptive analysis to examine data by analyzing behaviors and nuances of languages. An example of qualitative research is a study of their drinking habits of people. Conversely, quantitative research uses numerical statistics and is common in social and natural sciences. Research design refers to different strategies used by the researcher to logically and coherently integrate various components of the study to effectively handle the research problem. It entails an outline for data collection, measurement and analysis and is determined by the problem of the research. Different designs are used in different types of research and field of study (Kothari, 2003). This paper analyzes design strategies for different types of research methods.
Types of research designs
Case study design
This refers to an in-depth analysis of a specific research problem. The case study design is used to narrow down a wide field of research into a single or few researchable problems. The method is also useful in testing whether a given theory or model is applicable to a given phenomenon in the real world. The design uses a comprehensive contextual analysis of an event or condition to bring about much understanding of the complex research issues. It can also be utilized to add experience and strength to previous studies as well as providing a detailed description of specific and rare issues or phenomena.
The method is applicable to different research methodologies and is regularly used by social scientists. Limitations of the case study design is that it offers little basis to generalize its findings to a wider population, place or people. Extensive exposure to the study may make the researcher biased in his or her interpretation of study findings (De, 2001).
Causal research design
The design is used to determine the impact of changing a given phenomenon on the existing assumptions and norms. The causal effect occurs when a dependent variable changes due to variations in independent variable. The conditions necessary for causality include empirical association between the variables, cases must be as a result of varying independent variable and there must be no spurious effects. The design helps researcher to answer the question “why” (Kothari, 2003).
Limitation of the design is that not all relationships are causal but could be a result of sheer coincidence. The design implies that the “cause” must come before its “effect”, hence difficult to determine dependent and independent variables where two variables are causally related. The impact of extraneous factors makes it difficult to establish causal relationships and causality can only be inferred but not proven. The design is useful in both qualitative and quantitative methods of research (Kothari, 2003).
Cohort research design
The design is useful in medicine and applied sciences and is conducted in homogenous population. It uses quantitative framework to collect relevant data for the problem of research being investigated using observation methods. It can either be open or closed cohort design where in closed cohort the size of study population is remains constant as opposed to open cohort design (USC libraries, 2012).
The design is useful and mandatory in studies that measure risk factors for ethical reasons because you cannot deliberately expose people to bacteria for purposes of research. The researcher would instead use the already affected patients to conduct his or study. The study measures the possible cause before the occurrence of actual outcome; it therefore eliminates the debate on what is the cause and effect. The design can utilize both primary and secondary data and is also flexible (USC libraries, 2012).
Cross-sectional and longitudinal design
These design measures differences across a variety of subjects, people or phenomena but not change. It uses survey design to draw inferences about differences between subjects of the research at a given point in time. Conversely, longitudinal design is used to measure differences in the study subjects over time. Commonly used in social sciences and in quantitative research.
The design uses experimental and controlled group of homogenous subjects. The experimental group is manipulated to determine the impact of independent variable on the groups. It enables the researcher to identify the cause effect relationship between variables of study. Used in social sciences and quantitative research to determine the causes of phenomenon.
Descriptive research design
These provide the answers to questions of what, when, where, how and who. It obtains information on the status of the phenomenon in their natural environment. Is used to lay ground and provide valuable pointers for subsequent quantitative study designs. It collects adequate data needed for detailed analysis and recommendations. However, the design cannot be used to discover a perfect answer to invalidate a hypothesis. Is commonly used in qualitative methods of research and its findings cannot be replicated because it uses observational methods of data collection (USC libraries, 2012).
Research design is the logical structure undertaken to ensure that evidence gathered addresses the research problem unambiguously as possible by ensuring that evidences collected are consistent with the theory. Design is often confused with qualitative and quantitative research methods. Failing to distinguish between design and the method leads to the poor evaluation of designs. However, in principle, any design can be qualitative or quantitative and can employ any method of data collection. Research designs are useful in reducing the ambiguity of much research evidence to minimize the probability of drawing wrong causal inferences.
De, V. D. A. (2001). Research design in social research. London. SAGE.
Kothari C.R. (2003). Research Methodology; Methods and Techniques. New Delhi. New Age Int. Publishers.
USC libraries. (2012). Types of Research Designs. Organizing Your Social Sciences Research Paper. Retrieved on 31st July, 2012 from http://libguides.usc.edu