CMPS

• Association refers to the relationship or connection between two or more variables when changes in one variable are related to changes in another variable.
• An association can be observed through statistical analysis, indicating that changes in one variable are linked to changes in another variable, but it doesn't necessarily imply causation.
• Variables in an Association include the Dependent Variable (Outcome Variable), which is the variable being studied or predicted in an experiment or observational study, and the Independent Variable (Explanatory Variable), which is the variable manipulated or controlled by the researcher.
• Confounding Variables are additional variables that are related to both the independent and dependent variables and can influence the observed association between them.
• Bias is any systematic error in the design, conduct or analysis of a study that results in a mistaken estimate of an exposures effect on the risk of disease.
• There are different types of bias: Selective bias, when cases and controls or exposed and non-exposed individuals were selected for the observation of an association, and Information bias, when the means for obtaining information about the subjects in the study are inadequate or incorrect.
• Necessary and sufficient – a factor is both necessary and sufficient to cause a disease, Necessary but not sufficient - a factor is necessary but not sufficient alone to cause a disease, Sufficient but not necessary – a factor is sufficient but not necessary to cause a disease, and Neither sufficient nor necessary – factor is not sufficient or necessary to produce the disease.
• Hill’s causal criteria include the Temporal relationship, which states that the exposure to factor must have occured before disease, Strength of association, which is the relative risk of the disease after exposure to the factor, Replication of findings, which means that findings can be replicated by other researchers, Biological plausibility, which is the coherence with current biological knowledge, Consideration of alternate explanations, which involves taking into account and eliminating other views, Cessation of exposure, which is when the risk of disease declines when exposure stops, and
• Specificity of the association is a criteria used to differentiate between real and spurious associations in observational studies.
• To be a “real” association in observational studies, the design of the experiment must be considered.
• If a study is designed to select controls such a way that they tend to be nonexposed, an association of exposure with the disease might be observed.