In this second self-study course of the ‘Introduction to research in the ICU’ module, we move beyond basic statistics to provide a first introduction to key concepts in clinical studies. The reader may note that this course is about study populations and outcomes, while everything ‘in between’, such as inferential statistical methods, is missing. This is no accident. A good research hypothesis is the foundation of high-quality clinical research, and formulating a good hypothesis requires clear thinking about the intended patients (the target population) and about the way in which the hypothesis can be quantified and tested (the study endpoints). These concepts apply to practically all clinical study designs, from descriptive, predictive or observational comparative effectiveness studies to randomized controlled trials. Later modules in the Research Education Pathway will focus on specific study designs and inferential methods, such as diagnostic accuracy studies, predictive studies, or randomized trials.

This self-study course is a key component of Module 1 of the ESICM research education pathway and needs to be completed before attending the masterclass. Understanding the concepts contained in this module is key to getting the most out of the masterclass, as the masterclass will extend your knowledge and skills in this area.