Observational Research
Qualitative Research
No manipulation: Researchers don't introduce or change any variables that might influence the outcome.
Are also known as longitudinal or epidemiological studies. These involve large groups of people over an extended period of time to see how exposures affect their outcomes. For example exposure to 30 cigarettes per day. This type of study may look forward in time (prospective) or back in time (retrospective) (see diagram above) at various risk factors that cannot be controlled experimentally. These studies are observational, non experimental in design and often used to determine long term effects of a lifestyle, diet, or other interventions. Cohort studies may include a control comparison.
Case Series reports are retrospoctive in that they look back in time at certain exposures looking for associations with particular outcomes. As the title suggests the researcher will look at cases (eg those with lung cancer) & similar health subjects or controls (those without lung cancer).
A case series or case study in research involves the detailed analysis of a small group of individuals who share a common characteristic or condition. It provides a focused examination of their experiences, symptoms, treatments, and outcomes, aiming to generate hypotheses and contribute to medical knowledge.
Simply grouping case studies/reports together creates case series.
Correlational research is a non-experimental research method that investigates the relationships between variables. Unlike experiments, researchers don't manipulate or control any variables in a correlational study. Instead, they observe and measure two or more variables and assess the statistical relationship (correlation) between them.
They include: