Final answer:
The interpretation of odds ratios differs in cohort and case-control studies. In cohort studies, odds ratios can approximate relative risk, while in case-control studies odds ratios are used due to the inability to calculate incidence rates. Experimental design elements like randomization and control groups are crucial to ensure the validity of these measures.
Step-by-step explanation:
The interpretation of odds ratios varies depending on the study design. In cohort studies, which follow a group over time, the odds ratio can approximate the relative risk, comparing the likelihood of an event between an exposed group and an unexposed group. For case-control studies, which look retrospectively at factors affecting groups with and without a condition, odds ratios are used because the incidence rate cannot be directly calculated. An odds ratio greater than one indicates a positive association between exposure and outcome, while a ratio less than one suggests a negative association. A ratio close to one suggests no association.
Experimental design influences the integrity of the resulting data. Key components include random assignment, control groups, and possibly blinding of participants and researchers. Without controlling for these factors, the results may be influenced by lurking variables or confounders, which are variables that correlate with both the exposure and the outcome.