There are many reasons for collecting repeated measures data. Some examples are as follows:
• To ensure that a treatment is effective over a specified period of time. Often this will be done using a carefully planned trial with fixed timings for visits.
• To monitor safety aspects of the treatment over a specified period (repeated efficacy measurements are then incidental).
Applied Mixed Models in Medicine, Second Edition H. Brown and R. Prescott © 2006 John Wiley & Sons, Ltd ISBN: 0-470-02356-2
• To see how long a single dose of a drug takes to become effective by measuring drug concentration or a physiological response at fixed intervals (often over 24 hours). In this situation repeated measurements are taken at a single visit.
• Repeated observations are sometimes inherent in the measurement itself; for example, blood pressure monitors can take measurements as frequently as every 10 seconds.
• To monitorparticular groups of patients over time. Often these are retrospective studies where repeated measurements have been recorded in an unplanned fashion. For example, repeated observations on patients with a particular disease may be available from a hospital clinic.
Was this article helpful?