28 Feb 2024 Overlap of Primary Studies in Overviews
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In this webinar, Dr. Javier Bracchiglione explored general overview concepts, focusing on overlap of primary studies, current methods for addressing it, and pending challenges. Several methods have been proposed for dealing with overlap: overview authors may use decision rules, visual representations or statistical methods to describe or integrate overlap into the data analysis, the construction of matrices of evidence and the calculation of the corrected covered area — an index that estimates the percentage of overlap derived from a matrix.
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TITLE: Overlap of Primary Studies in Overviews
WHEN: Wednesday, February 28th, 2024 at 12:00 noon PST [convert to your local time]
WHERE: free online webinar.
SPEAKER: Dr. Javier Bracchiglione, MD, Lecturer of Evidence-Based Medicine and Biomedical Research Methodology at Universidad de Valparaíso, Chile.
About the topic: Overviews are a research design that aims to synthesize the available evidence for one or more clinical questions, considering systematic reviews as the unit of analysis. Due to the use of systematic methods, overviews are also commonly known as ‘systematic reviews of systematic reviews’. However, the conduction of overviews poses some specific and unique challenges, such as the overlap of primary studies. In the context of overviews, overlap can be defined as the multiple counting of a unique primary study included in two or more systematic reviews within an overview. If not properly identified and addressed, overlap may potentially result in misleading findings due to overly precise estimates and bias towards the effect of the most overlapped studies. Several methods have been proposed for dealing with overlap: overview authors may use decision rules, visual representations or statistical methods to describe or integrate overlap into the data analysis, but probably the most recommended methods include the construction of matrices of evidence and the calculation of the corrected covered area —an index that estimates the percentage of overlap derived from a matrix. However, some authors still inadequately address (or even ignore) overlap. Furthermore, certain key issues are still insufficiently explored, such as the assumptions made when describing overlap. In this webinar, Dr. Javier Bracchiglione explored general overview concepts, focusing on overlap of primary studies, current methods for addressing it, and pending challenges.
About the speaker: Dr. Javier Bracchiglione is a general practitioner with a master degree in Applied Clinical Research in Health Sciences from the Universitat Autònoma de Barcelona, Spain. He is a lecturer of Evidence-Based Medicine and Biomedical Research Methodology at Universidad de Valparaíso, Chile, and a predoctoral researcher at the Iberoamerican Cochrane Centre in Barcelona, Spain, where he is currently developing and testing methods to assess overlap of primary studies within overviews.
About the TI Methods Speaker Series: The TI Methods Speaker Series are offered free of charge and everyone is welcome. The event is usually held at noon on the last Wednesday of each month via Zoom videoconference. The presentations are recorded and the video recordings are posted online. Click here to view the list of talks offered in 2024.
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