This document presents a critical appraisal of two study designs: a cross-sectional study and a case-control study. The analysis evaluates the methodological quality of each study, addressing questions related to inclusion criteria, subject description, measurement validity and reliability, confounding factors, and statistical analysis. The cross-sectional study examines the possibility of biasedness, while the case-control study focuses on evidence-based aromatherapy practices. The assessment highlights the strengths and weaknesses of each study design, providing justifications for the answers and comparing and contrasting the findings. The document also includes references and addresses the treatment effects, precision of estimates, and the overall impact of the studies. The document aims to inform synthesis and clinical decision-making in health care, emphasizing the importance of rigorous research and critical evaluation.