hey everyone welcome back to the Met analysis Academy channel in this video we're going to discuss key differences between systematic reviews and metanalysis if you're new to this channel my name is randerson cardoo I am a cardiologist in Boston in the United States and in this channel we talk about systematic reviews metaanalysis research career Publications especially how Publications with metaanalysis can boost your career can help you achieve your goals so if you're interested in this type of content hit the Subscribe button and make sure to stay tuned in to future videos as well all right so let's discuss what are the differences between systematic reviews and met analysis first let's start with systematic review what is this what makes a review systematic so let's use the cochine definition for systematic review cochine says that a systematic review is the process to identify a praise and synthesis ize all the empirical evidence that meets pre-specified criteria to answer a specific well-defined research question so there's important things to unpack in all these elements the first thing is that a systematic review is pre-specified and follows specific methods this is really key for you to understand what a systematic review is in doing a systematic review would Define a very specific question that has a population an intervention maybe a control group and the specific outcomes that we're interested in so we pre-specify all these components and then we systematically search we apply systematic methods to identify all the studies that fit these inclusion or eligibility criteria and there are methodic ways of going about this there are specific ways on how you're going to search how you're going to three OD studies include them in your systematic review so that's essentially what a systematic review is it's an explicit method to identify all studies that fit a pre-specified research question and what is a metanalysis then and how does it contrast to a systematic review well imagine you do a systematic review and you find maybe 20 papers 15 papers 30 papers that fit a specific pre-specified question how do you make sense of all of this data that's where a metaanalysis comes in a metaanalysis is a statistical technique it's math it's the quantitative synthesis of all these studies that you identify in doing a systematic review so a metaanalysis is a powerful tool a powerful statistical tool that is combined with a systematic review the systematic review is the process to find the studies the metanalysis is the process to quantitatively analyze them as a whole to provide a mathematical synthesis of all those studies so essentially a metaanalysis takes all this data and analyzes it collectively you can think of it as a puzzle a systematic review would be the process of identifying and organizing all the pieces of the puzzle a met analysis the process of putting it together to have a unified conclusion of all of those studies and now that you understand this you can see that potentially you could even do a met analysis without doing a systematic review you could just put the results of two or three or four or five studies together without doing a systematic review you could analyze them together combined but not go through the rigorous systematic process of identifying all the studies on a given topic that could be done but it's not because it would introduce bias if I selectively choose the studies that I want to put in a met analysis I could pick the ones that share my opinion on the topic and ignore others but when you do a systematic review you pre-specify your eligibility criteria and you include all the studies that fit those criteria such that you minimize bias when doing your meta analysis because now you're going to look at all the studies that fit a certain question and not just a selective group of studies that you pick and choose among multiple others now that you understand this you can also figure out that there are important differences when reporting the results of a systematic review of alone and a systematic review with metaanalysis if you are going to report just a systematic review this will be a qualitative report of the results it will be a narrative report you will say I found 10 studies one of them found this the other one found that and then this other one in contrast showed a different finding so you're going to qualitatively report the results of different studies in a narrative review a meta analysis when you add that to a systematic review again you look at all the studies together you combine their statistical results mathematically so you have a forest plot you have a quantitative synthesis of these studies together so a forest plot is a quantitative report of aat analysis as opposed to a systematic review which is more of a narrative a qualitative report in future videos you will see a full explanation of what is a forest plot and how to understand it how to take the data from it but in short these for plots display the results of each individual study and then at the bottom the results of the metaanalysis the results of the quantitative analysis of all the studies together and to finalize this video you may be asking why would anyone ever do just a systematic review if uh met analysis is so much better if it analyzes the studies collectively together gives a unified report of called the study results why not always do it because you can't always combine the studies and the studies may have important methodological differences they may be analyzing different outcomes outcomes measured in different ways slightly different populations so you may not be able to combine the studies mathematically to generate a meta analysis that's the main reason why anyone would do just a systematic review and not a met analysis the other reason being of course if they don't know how to do a metaanalysis and of course you can learn that in the metaanalysis academy with our team so using our puzzle analogy let's say that you did a systematic review and you found all the pieces of this puzzle but if you can't connect them if you can't put them together you can't finalize the puzzle you can't really do the Met analysis the studies have to be similar enough to each other for you to do a met analysis after a systematic review so in conclusion a systematic review is the process is the methods to systematically identify all studies that fit a pre-specified research question and with that minimized bias a metanalysis is when you get all these studies together and you combine them into one result so if you want to learn how to do both a systematic review and a metanalysis I want to invite you to join the weight list of the metanalysis academy in our program you will learn all the tools to do everything from the developing your idea doing all the methods searching the literature triaging the studies running the statistics form met analysis and then of course writing your manuscript so if you want to learn all of this join us in the next edition of The metaanalysis Academy I'll see you there [Music]