Practical guide to understanding multivariable analyses: Part A.

Multivariable analyses are complex statistical methods to evaluate the impact of multiple variables on outcomes of interest. Books have been written on each of these methods detailing the mathematical and statistical objectives and processes. However, we have found very little in the way of brief reports that help the nonstatistically trained physician obtain a basic understanding of multivariable analyses in order to have some understanding of the increasing literature using these methods. This work is organized in 2 parts. This article, Part A, addresses the "big 4" algebraic methods of multivariable analysis. The primary focus of Part A is to present a brief "primer" to help the reader understand the methods and uses; it expressly avoids the many details of statistical assumptions, calculations, and myriad branching alternatives. Part B will concentrate on conjunctive consolidation and will focus on enough information to allow the interested reader to actually perform the analysis. For the statistical scholar, we have included references to several voluminous serious works.