Study Analysis: Revelation of Truth, or Murder by Numbers?

What type of analyses are we to expect when we read a study that attempts to measure success or failure of a specific spine procedure? Most analyses are divided into descriptive and analytical statistics, which should be clearly described in the methods section of a study. Descriptive statistics are most frequently used to provide general information about the patients and factors that may be related to outcomes. In one sense, they set the stage for some of the analytical methods (such as control for confounding) that may be needed to ensure the most accurate estimate of a study treatment effect. Analytical statistics allow for evaluation of treatment effects and the associations between factors. A prospective study allows one to collect all known and suspected potential confounders. For retrospective studies, investigators are limited to what has already been collected and often do not have access to factors that likely influence outcome (eg, smoking status).