howMed Know Yourself
Spurious Association Sometimes an observed association between a disease and suspected factor may not be real. For example a study … Read More »
Spurious Association, Multifactorial Causation and Evidence of Causation
Quasi Experimental Studies
Quasi experimental designs are based on the same structure as experimental designs but lack the randomization, control, or both. These … Read More »
Non-Randomized Trials
Trial is from the French ‘trier’ (to try). Trial may be: • Clinical trial –in which we apply therapeutic interventions … Read More »
Randomized Controlled Trials
An epidemiological experiment in which subjects in a population are randomly allocated into groups, usually called study and control groups … Read More »
Cohort Studies
Cohort is an ancient Roman military unit of 300-600 men, a group of soldiers marching forward in battle. Cohort studies … Read More »
Differences between Case Control and Cohort Studies
The differences between case control and cohort studies may be summarized as follows: Case Control Study Cohort Study • Proceeds … Read More »
Case Control Studies
In case control study, we start with diseased group (“cases”); which we compare with non-diseased group (“controls”). We look back … Read More »
Ecological Studies
In ecological studies, we consider aggregates of individuals. Aggregates often defined by units e.g. geographic region, school or health care … Read More »
Cross-Sectional Studies
Cross sectional studies are conducted at a single point in time or over a short period of time. There is … Read More »
Case Reports and Case Series
A case report is a detailed report by a physician of an unusual disease in a single person. The population … Read More »
