The concept of making inferences from research data is discussed in this article. Three hypothetical examples of research projects in O&P are developed. In each example, the emphasis is ondrawing inferences from research data rather than the statistical methods used.The first research example compares patient ratings of two spinal orthoses using the t-testfor independent means. A hypothetical data set is used to illustrate common statistical inferences made from the analysis. Practical inferences also are examined.The second research example uses a one-way analysis of variance (ANOVA) and post-test comparisons to evaluate four lengths of a wrist-hand orthosis for carpal tunnel syndrome. A hypothetical data set is analyzed, and common statistical and practical inferences are illustrated.The third research example uses the method of multiple regression analysis. This example introduces the concept of significant explainer variables, percentage of variance explained and prediction models. In each case, appropriate statistical and practical inferences are made from the hypothetical data.The three research examples distinguish between the important concepts of statistical inference and inferences of practical significance. These two key concepts are developed and discussed in some detail.