Clinical research - Issues in data collection

This focus issue of Spine is dedicated to measurement of clinical outcomes. At the practical level this is hard to do; however, at a scientific level it is essential. Those involved in clinical research or interested in collecting data in their own practices struggle with decisions about which instruments to use in collecting data and when to use them. Even when the relevant outcomes of a treatment are identified, collecting that information remains problematic. To be most efficient at designing and collecting the appropriate data elements, careful thought must be given to the exact questions they are to address. The formulation of a good research question, up front, informs the clinician or researcher about the most appropriate data elements to be collected. In a clinical trial, the ability to determine the better of two treatments is often the product of the trial hypothesis or question, the data elements chosen to evaluate the treatments in question, and the magnitude of change in scores over time needed to consider one treatment preferable to the other. Even with these clarified, the appropriate sample size must be determined, given the smallest clinically relevant difference in outcome and the variability in measures. This is necessary to have sufficient statistical power to determine whether the efficacy of one treatment is superior to the other. Having determined this, the clinician or researcher can then consider the many practical aspects of actually performing a study or sophisticated clinical trial. This article focuses on data collection and the phases in a study or clinical trial that necessitate major considerations over time. There is a paucity of surgical trials from which to glean perspective on how best to organize and run such a trial. A basic understanding of issues related to data collection will be useful to investigators considering a trial.