What do visit windows in clinical trials refer to?

Visit windows in clinical trials refer to the number of days surrounding a specific scheduled visit date that a patient is permitted to attend a study visit. This flexibility accommodates variations in patient availability and logistical challenges while ensuring that the necessary data is collected within an acceptable time frame to maintain the integrity of the study design. By defining a visit window, researchers can better manage patient scheduling, adherence to protocol, and data consistency while still maintaining the rigor of the trial. This practice helps to minimize disruptions in the continuity of care and ensures that the patient's response to the treatment can be accurately assessed within the context of the study's objectives.