نتایج جستجو برای: observational studies

تعداد نتایج: 1500859  

Journal: :caspian journal of internal medicine 0
karimollah hajian tilaki

background: confounding can be thought of as mixing the effect of exposure on the risk of disease with a third factor which distorts the measure of association such as risk ratio or odds ratio. this bias arises because of complex functional relationship of confounder with both exposure and disease (outcome). in this article, we provided a conceptual framework review of confounding issues in epi...

آثار, شکرالله, ایوبی, فاطمه, جلال پور, شیلا, رحمانی, محمدرضا, رضائیان, محسن,

Background and Objective: Studies in the health sciences is comprised of observational and intervention. A major part of health sciences research has been allocated to the observational studies. Designing and doing studies based on scientific guidelines that include the entire process, leads to studies validation and also results can be generalized to the community. Thus, for standardizing ...

تاجیک, پروین, رضایی, محسن, صالحی, علیرضا, صحت, مجتبی, هلاکویی نایینی, کورش, پورالعجل, جلال, یزدی زاده, بهاره,

Background & Objectives: Observational studies are not often reported in detail and clear enough, so that assessment of the strengths and weaknesses of these studies is not straightforward. To improve the reporting of observational studies, a checklist of items called ‘Strengthening the Reporting of Observational Studies in Epidemiology’ (STROBE) was developed by some experts in October 2007. T...

Journal: :Heart 2004
P Jepsen S P Johnsen M W Gillman H T Sørensen

Correspondence to: Dr Peter Jepsen, Department of Clinical Epidemiology, Aarhus University Hospital, Vennelyst Boulevard 6, 8000 Aarhus C, Denmark; pj@soci. au.dk _________________________ T he aim of this paper is to review the most important methodological strengths and limitations of observational studies of humans, as opposed to experimental studies. The names ‘‘observational’’ and ‘‘experi...

Journal: :iranian journal of psychiatry 0
behzad hajarizadeh unaids country office, tehran, iran behnam sadeghirad neuroscience research centre, university of medical sciences, kerman, iran ali-akbar haghdoost department of epidemiology, kerman university of medical sciences, physiology research centre, kerman, iran london school of hygiene and tropical medicine, london, uk ali mirzazadeh kerman university of medical sciences, physiology research centre, kerman, iran

abstract: in contrast to traditional reviews, systematic reviews explore theliterature on a specific topic comprehensively using a well-defined protocol and recruit the findings of eligible studies after the assessment of their qualities, using a clear and reproducible method. checking the assumptions, we may merge the findings of recruited studies in a systematic review and use metaanalysis te...

Journal: :Plastic and Reconstructive Surgery 2010

2010
PAUL R. ROSENBAUM

Some experiments involve more than one random assignment of treatments to units. An analogous situation arises in certain observational studies, although randomization is not used, so each assignment may be biased. If each assignment is suspect, it is natural to ask whether there are separate pieces of information, dependent upon different assumptions, and perhaps whether conclusions about trea...

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