 When you embark upon research it's important to understand what types of studies you can do. Now there are many classification systems and in this lecture I provide you with one such system. We see that we can do research by form of case study, case control series, cross sectional series, cohort series and then clinical trials where we're actually going to do some intervention. Those would be trials with independent concurrent controls, trials with self controls, trials with external controls and even uncontrolled trials. And then very importantly there are the meta-analyses and reviews. Now many of these can be mixed and matched in your research. Please have a read through this text and become familiar with the types of research that is out there.