Research Design refers to the blueprint to be followed by the researcher. As it provides a framework for the entire research project, the design will need to answer some important questions on how the goals of the research project will be accomplished. Why is the study being made? What type of data is required? Will there be a control group? What techniques and statistics will be used to collect and analyze the data? How will neutrality, reliability and validity be proven? And so on. A good research design constitutes a solid foundation for the research work to follow.
Below are descriptions, links to library resources from Reference Services and web resource links on the topics of research methodology and methods. This guide is by no means an exhaustive source.
"The Case Study method takes a situation as given and tries to find out what it particularly means to the participants. Commonly, case studies are associated with qualitative research, but often they combine different research techniques. They can illuminate quantitative findings and can incorporate quantitative data. The method usually involves the examination of one or, possibly, two or three particular cases in-depth and holistically. A case study can take months or even years to complete, which allows mature consideration of the findings, correction of misunderstandings, filling of gaps in the data, investigation of new ideas arising from the data and a longitudinal view" (Basic research methods : an entry to social science research).
Researchers in education and a number of social science fields often conduct this type of research method and it is also a method employed when there are not the resources for a large study.
"Case–control Studies represent a sampling strategy in which the population under study is selected based on the presence (case) or absence (control) of an event of interest. The underlying purpose of these studies is to identify causal factors of the events of interest by comparing characteristics of both groups. Case–control studies start by identifying the study population, from which cases are identified and their exposure status is determined retrospectively. Then, a control group of study subjects is sampled from the entire source population that gives rise to the cases. Case–control studies are frequently one of the first approaches used in the etiological study of a disease or health condition. This is in part due to the possibility of incorporating in the analysis many exposition factors simultaneously and relatively quickly and inexpensively. Therefore, case–control studies represent a cost-effective way of identifying risk and protective factors and generating hypotheses for subsequent, methodologically stronger studies" (Case-control studies in traffic psychology (Ch. 3, publisher summary only)).
"A Clinical Study involves research using human volunteers (also called participants) that is intended to add to medical knowledge. There are two main types of clinical studies: clinical trials (also called interventional studies) and observational studies" (ClinicalTrials.gov).
Cohort Studies look at a well-defined group of subjects who share a common characteristic or experience.
In epidemiology, cohort studies investigate those who are at risk of developing a specific disease or health outcome.
Example: The Air Force Health Study (AFHS) is a longitudinal, prospective epidemiologic study of more than 2,700 men followed for approximately 20 years. The cohort consisted of Air Force personnel who had participated in Operation Ranch Hand.
Cross-sectional Studies make observations of either an entire population or a representative subset of the population at a specific point in time. Like a photographic "snap-shot."
It is an observational type of study, and trends can be monitored over time however, when serial cross-sectional studies are conducted. But unlike longitudinal studies (performed over time), where the variables of the research can change during a study, a cross-sectional study observes a single instance with all variables remaining the same throughout the study.
In education a cross-sectional study is particularly helpful in understanding how students who scored within a particular grade range in the same preliminary courses perform with a new curriculum. This type of study can also help market researchers identify target demographics.
Experimental Studies are ones where researchers introduce an intervention and study the effects. Experimental studies are usually randomized, meaning the subjects are grouped by chance.
Randomized controlled (intervention) trial (RCT): Eligible subjects are randomly assigned to one of two or more groups. One group receives the intervention (such as a new drug) while the control group receives nothing or an inactive placebo. The researchers then study what happens to subjects in each group. Any difference in outcomes can then be linked to the intervention.
Natural/Quasi Experiments: Natural experiments are often used when controlled experimentation is not possible; such as when subjects can not be practically or ethically assigned treatments.
Experimental Settings: Experiments can be conducted in laboratory (artificial) and field (real-life) settings. Field research can help resolve gaps in data and collect supporting/ancillary material. "However, because field studies, by their very nature, do not control extraneous variables, it is exceedingly difficult to ascertain which factor or factors are more influential in any particular context. Bias can also be an issue if the researcher is testing a hypothesis" (Encyclopedia of Research Design).
Focus Groups will consist of several or more participants discussing a particular topic or a set of questions in a controlled environment. Focus groups provide insights into how people think and provide a deeper understanding of the phenomena being studied. Market researchers find focus groups useful in testing new products and concepts. Researchers can be facilitators or observers.
Interviews are one-on-one conversations where the interviewer is asking questions to gather specific information from the participants. Interviews are good complements or enhancements to data derived from surveys and questionnaires. It can be a good technique to employ when probing for information on sensitive topics. Field researchers might employ informal, conversational interviews to both help develop relationship with participants and incorporate the data into their field notes.
Observational Studies are types of study in which subjects are observed or certain outcomes are measured, without any attempt to affect the outcome (e.g., no treatment is given). Ecologists conduct observational studies in order to measure basic attributes of organisms, populations and communities in their natural setting without disturbance. Such data collected can help to understand behavioral or environmental changes.
Some observational research methods include case reports, chart reviews, and longitudinal studies of large cohorts followed over time.
Extremely important to recognize, however, is that observational studies cannot prove cause-and-effect. Researchers should be aware of, and address, the limitations of observational studies in their research.
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Why use sampling? Sampling efficiently gets information on a large population when you can otherwise not get information on every subject in the population. Therefore, a representative sample of a population will suffice.
There are two main branches of sampling methods, probability sampling and non-probability sampling.
When choosing a sampling method, consider characteristics of the population to be studied, the level of precision required and the resources available.
Probability Sampling: every unit of the population has a known chance of participating in the study.
Non-probability Sampling: probability of selection is unknown or zero, so not every unit of the population has a chance to participate in the study.
Survey Research: This is an organized method of obtaining data from research participants via written, electronic, or oral questioning, which can be analyzed to reach conclusions about the question being investigated within a sample of the population. Surveys are frequently used by multiple disciplines to look for trends, behavior and the "bigger picture;" however, unless an experimental design is used, survey research does not allow for the drawing of causal inferences.
A questionnaire is a set of questions that can be qualitative, quantitative, or mixed, in nature. Questions can be open-ended (which requires the participant to formulate answers in their own words) or closed-ended (which requires the participant to choose a response from a list of options).
