Final answer:
The statement is false; observational studies are frequently used in population health research when it is not possible or ethical to conduct experimental studies. They are important for studying real-life situations and can include larger sample sizes than experimental studies, which is often advantageous for health research.
Step-by-step explanation:
The statement that observational studies are rarely used in population health research due to ethical and feasibility issues is false. In reality, when it is not possible or ethical to conduct experimental studies, observational studies can provide crucial insights into health-related behaviors and outcomes. For example, it would be unethical and impractical to conduct an experiment to determine the effects of smoking by forcing subjects to smoke. Instead, researchers observe existing smokers and compare their health outcomes to those of non-smokers.
Observational studies can often include larger sample sizes and therefore more data, which can be advantageous for studying population health. They typically are less expensive and easier to conduct compared to experimental studies. Although they do not allow for control over variables and cannot definitively establish cause-and-effect relationships, observational studies are of vital importance in contexts where controlled experiments are unfeasible or unethical.
Additionally, observational studies can take the form of clinical or case studies, which may focus on a smaller number of individuals, allowing researchers to delve deeply into particular health conditions. While these studies have limitations, including lower levels of control and potential for bias, they are essential in situations where direct manipulation of variables to test outcomes is not practical or ethical.