Study design refers to the overall strategy or plan that researchers use to conduct a study. It outlines how data will be collected, analyzed, and interpreted to answer specific research questions. Common types of study designs include experimental, observational, and longitudinal studies, each serving different purposes and providing various levels of evidence. A well-structured study design is crucial for ensuring the validity and reliability of the results. It helps minimize biases and confounding factors, allowing researchers to draw accurate conclusions. Proper design also facilitates the replication of the study by other researchers, which is essential for confirming findings in the scientific community.