Objective: To compare techniques to analyze the content validity of measurement instruments applicable to nursing care research through a practical case. Method: Secondary study derived from validating the Hospital Survey on Patient Safety (HSOPS) in a Chilean hospital. The study setting was hospital care, with a population focused on nursing staff and a sample of 12 expert nurses who are teachers or have clinical experience in quality and patient safety. Design and content validity test based on three phases: identification of primary methods, calculation of methods, comparison of similarities and differences of methods. Results: Lawsche, Tristan-López, Lynn, Polit et al. methods are similar. The modified kappa value is similar to the content validity index (I-CVI) value, with a slight variation when penalizing the value by probability according to chance. There are significant differences between all methods and Hernández Nieto's content validity coefficient (CVC). Conclusions: The Polit et al. method is more rigorous, and its mathematical formulation is better justified, providing solidity to clinical nursing research. Furthermore, the Hernandez-Nieto method is suggested when validating more than one characteristic.