Hello, and welcome back to Evidence-Based Toxicology course. This module will teach you about systematic review and meta-analysis. Both those terms are really tied together because meta-analysis is part of systematic review. The first lesson will give you historical perspective of systematic review and how to perform systematic review. Dr. Navis who will be giving this lecture will explain to you step by step all of the process of systematic review based on your own research and your own subjects. And she will give you also a historical perspective, describe people who introduced systematic review in the field and pulled this field forward to the stage we are at now. And she will explain to you why systematic review is so important on a really nice example. For example, the corticosteroid use, and pretty much you are pregnant of deliveries when the cortico shots are given to mothers before C section which increase the survival of preemies drastically. This was a very long debate about the usage of this corticosteroid. Are they good? Are they bad? What are the effects of those? And then after a systematic review of the old existing data was performed and analyzed, it was clear the beneficial effect of using this corticosteroid shots for survival of premature babies. Another example from the clinics also is using of beta blockers for treating their myocardial infection, was also, really, the literature about it was not conclusive enough. So some studies were showing a beneficial effect of beta blockers, some studies were inconclusive, some were negative. After performing a systematic review, it was clear that beta blockers can be used for myocardial infarction treatment. The next lesson in this module will be on meta-analysis. Meta-analysis is a part of systematic review. Not every single systematic review will have a meta-analysis part, but meta-analysis does exist without systematic review. And this lesson will be given you by Dr. Goodman. She will explain you how to perform meta-analysis, which is what are the limitations and advantages of meta-analysis, and what is meta analysis? This is the analytical tool which allows you to pull all data together and analyze them together. So this is analysis of analysis. And by pulling all the evidence together, you can make a conclusion by using the statistical tools whether they're all darted together are significant or not significant. For example, imagine you have a correlation between or there is an assumption that the risk relation between obesity and exposure to certain environmental chemical. But there is many, many literature or publications describing either there is a correlation, or there is no correlation, or there is some relationship which is inconclusive. How you can make conclusion from this? You put them all together, perform systemic review of this relationship, you analyze the quality. You exclude some publications which doesn't have this quality control or inclusion, exclusion criteria. And then you end up with a solid body of literature for meta-analysis. When you pull them together, you can make a conclusion, yes, this chemical induce obesity in population, or no, this chemical doesn't do anything for the obesity. So this is what meta-analysis can try to help you with.