scholarly journals A Fundamental Equivalence between Randomized Experiments and Observational Studies

2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Stephen R. Cole ◽  
Michael G. Hudgens ◽  
Jessie K. Edwards
Keyword(s):  
General Solution ◽  
Observational Studies ◽  
Common Ground ◽  
Mathematical Proof ◽  
Randomized Experiments ◽  
Worked Example ◽  
Study Designs

AbstractA fundamental probabilistic equivalence between randomized experiments and observational studies is presented. Given a detailed scenario, the reader is asked to consider which of two possible study designs provides more information regarding the expected difference in an outcome due to a time-fixed treatment. A general solution is described, and a particular worked example is also provided. A mathematical proof is given in the appendix. The demonstrated equivalence helps to clarify common ground between randomized experiments and observational studies, and to provide a foundation for considering both the design and interpretation of studies.

The Dietary Inflammatory Index and Human Health: An Umbrella Review of Meta-Analyses of Observational Studies

2021 ◽  
Author(s):  
Wolfgang Marx ◽  
Nicola Veronese ◽  
Jaimon T Kelly ◽  
Lee Smith ◽  
Meghan Hockey ◽  
...  
Keyword(s):  
Chronic Disease ◽  
Health Outcomes ◽  
Observational Studies ◽  
Dietary Inflammatory Index ◽  
Credibility Assessment ◽  
Umbrella Review ◽  
Inflammatory Index ◽  
Increased Risk ◽  
Meta Analyses ◽  
Study Designs

ABSTRACT Numerous observational studies have investigated the role of the Dietary Inflammatory Index (DII®) in chronic disease risk. The aims of this umbrella review and integrated meta-analyses were to systematically synthesize the observational evidence reporting on the associations between the DII and health outcomes based on meta-analyses, and to assess the quality and strength of the evidence for each associated outcome. This umbrella review with integrated meta-analyses investigated the association between the DII and a range of health outcomes based on meta-analyses of observational data. A credibility assessment was conducted for each outcome using the following criteria: statistical heterogeneity, 95% prediction intervals, evidence for small-study effect and/or excess significance bias, as well as effect sizes and P values using calculated random effects meta-analyses. In total, 15 meta-analyses reporting on 38 chronic disease-related outcomes were included, incorporating a total population of 4,360,111 subjects. Outcomes (n = 38) were examined through various study designs including case-control (n = 8), cross-sectional (n = 5), prospective (n = 5), and combination (n = 20) study designs. Adherence to a pro-inflammatory dietary pattern had a significant positive association with 27 (71%) of the included health outcomes (P value < 0.05). Using the credibility assessment, Class I (Convincing) evidence was identified for myocardial infarction only, Class II (Highly suggestive) evidence was identified for increased risk of all-cause mortality, overall risk of incident cancer, and risk of incident site-specific cancers (colorectal, pancreatic, respiratory, and oral cancers) with increasing (more pro-inflammatory) DII score. Most outcomes (n = 31) presented Class III (Suggestive) or lower evidence (Weak or No association). Pro-inflammatory dietary patterns were nominally associated with an increased risk of many chronic disease outcomes. However, the strength of evidence for most outcomes was limited. Further prospective studies are required to improve the precision of the effect size.

scholarly journals Strengthening the Reporting of Observational Studies in Epidemiology (STROBE): Explanation and Elaboration. Translation to Russian

2021 ◽  
pp. 1-10
Author(s):  
Jan P. Vandenbroucke ◽  
Erik Von Elm ◽  
Douglas G. Altman ◽  
Peter C. Gotzsche ◽  
Cynthia D. Mulrow ◽  
...  
Keyword(s):  
Observational Studies ◽  
Empirical Studies ◽  
Observational Research ◽  
Case Control Studies ◽  
Quality Of Reporting ◽  
Cross Sectional ◽  
Useful Flow ◽  
Study Designs ◽  
Strobe Statement

Much medical research is observational. The reporting of observational studies is often of insufficient quality. Poor reporting hampers the assessment of the strengths and weaknesses of a study and the generalisability of its results. Taking into account empirical evidence and theoretical considerations, a group of methodologists, researchers, and editors developed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) recommendations to improve the quality of reporting of observational studies. The STROBE Statement consists of a checklist of 22 items, which relate to the title, abstract, introduction, methods, results and discussion sections of articles. Eighteen items are common to cohort studies, case-control studies and cross-sectional studies and four are specific to each of the three study designs. The STROBE Statement provides guidance to authors about how to improve the reporting of observational studies and facilitates critical appraisal and interpretation of studies by reviewers, journal editors and readers. This explanatory and elaboration document is intended to enhance the use, understanding, and dissemination of the STROBE Statement. The meaning and rationale for each checklist item are presented. For each item, one or several published examples and, where possible, references to relevant empirical studies and methodological literature are provided. Examples of useful flow diagrams are also included. The STROBE Statement, this document, and the associated Web site (http://www. strobe-statement.org/) should be helpful resources to improve reporting of observational research. This article is the reprint with Russian translation of the original that can be observed here: Vandenbroucke JP, von Elm E, Altman DG, Gotzsche PC, Mulrow CD, et al. Strengthening the Reporting of Observational Studies in Epidemiology (STROBE): Explanation and Elaboration. PLoS Med 2007;4(10):e297. doi:10.1371/journal.pmed.0040297

Causal Impact

2019 ◽  
pp. 203-218
Author(s):  
Daniel Westreich
Keyword(s):  
Public Health ◽  
Health Policy ◽  
Implementation Science ◽  
Public Health Policy ◽  
Observational Studies ◽  
Epidemiologic Methods ◽  
Hierarchy Of Evidence ◽  
Causal Impact ◽  
Study Designs ◽  
Impact Framework

In Chapter 9, the author discusses the causal impact framework, an approach to epidemiologic methods that can be used to move from internally valid estimates to externally valid estimates to valid estimates of the effects of population interventions. Such work is essential if epidemiologists want the results of their experimental or observational studies to directly inform public health policy decisions. The bulk of this chapter outlines and describes an approach to epidemiologic methods relevant to implementation science. The author summarizes the entire book by briefly addressing the lessons of the previous chapters for the so-called hierarchy of evidence (hierarchy of study designs).

scholarly journals A Primer on Mixed Methods for Pediatric Researchers

2019 ◽  
Vol 44 (8) ◽  
pp. 905-913 ◽  
Author(s):  
Yelena P Wu ◽  
Janet A Deatrick ◽  
Elizabeth L McQuaid ◽  
Deborah Thompson
Keyword(s):  
Mixed Methods ◽  
Mixed Methods Research ◽  
Observational Studies ◽  
Family Health ◽  
Intervention Development ◽  
Central Component ◽  
Children And Families ◽  
Research Teams ◽  
Study Designs ◽  
Answer Format

Abstract Objective To provide a primer on conducting and analyzing mixed methods research studies, and to provide guidance on the write-up of mixed methods research. Methods A question and answer format is used to provide an overview of mixed methods research study designs, tasks and considerations related to conducting and analyzing mixed methods studies, and recommendations for the write-up of results for mixed methods studies. Results Individuals who conduct mixed methods research are encouraged to delineate the quantitative, qualitative, and mixed methods features of the research and how these features fit with the overall study questions. Research teams will benefit from including individuals with expertise in qualitative, quantitative, and mixed methods research. Data integration should be a central component to the analysis and write-up of mixed methods research. Conclusions Increasing the use of mixed methods research in the field of pediatric psychology will contribute to advances in observational studies with children and families, intervention development and evaluation, and creation of new tools and assessments that aim to optimize child and family health outcomes.

scholarly journals UNDERSTANDING ON STRATEGIES OF TEACHING MATHEMATICAL PROOF FOR UNDERGRADUATE STUDENTS

2018 ◽  
Vol 37 (2) ◽  
Author(s):  
Syamsuri Syamsuri ◽  
Indiana Marethi ◽  
Anwar Mutaqin
Keyword(s):  
Undergraduate Students ◽  
Mathematical Thinking ◽  
Mathematical Proof ◽  
Public University ◽  
Structural Method ◽  
Worked Example ◽  
Proof Construction ◽  
Main Instrument

Abstract:Many researches revealed that many students have difficulties in constructing proofs. Based on our empirical data, we develop a quadrant model to describe students’ classification of proof result. The quadrant model classifies a students’ proof construction based on the result of mathematical thinking. The aim of this article is to describe a students’ comprehension of proof based on the quadrant model in order to give appropriate suggested learning. The research is an explorative research and was conducted on 26 students majored in mathematics education in public university in Banten province, Indonesia. The main instrument in explorative research was researcher itself. The support instruments are proving-task and interview guides. These instruments were validated from two lecturers in order to guarantee the quality of instruments.Based on the results, some appropriate learning activities should be designed to support the students’ characteristics from each quadrant, i.e: a hermeneutics approach, using the two-column form method, learning using worked-example, or using structural method. Keywords:proof, proving learning, undergraduate, quadrant model   MEMAHAMI STRATEGI PENGAJARAN PEMBUKTIAN MATEMATIS DI PERGURUAN TINGGI Abstrak: Banyakpeneliti pendidikan matematika menyatakan bahwa siswa mengalami kesulitan dalam mengonstruksi bukti. Berdasarkan kajian empiris, penulis membangun suatu model kuadran untuk mendeskripsikan kategori konstruksi bukti yang dibangun siswa. Model kuadran tersebut mengklasifikasikan konstruksi bukti berdasarkan cara berpikir matematis saiwa. Adapun tujuan dari artikel ini ialah mendeskripsikan pemahaman siswa dalam mengonstruksi bukti berdasarkan model kuadran serta memberikan saran strategi pembelajarannya. Penelitian ini merupakan penelitian eksploratif yang melibatkan 26 mahasiswa Jurusan Pendidikan Matematika pada universitas negeri di Provinsi Banten. Instrumen utama dalam penelitian eksploratif adalah peneliti sendiri. Instrumen pendukungnya ialah tugas pembuktian matematis dan panduan wawancara. Kedua instrumen pendukung tersebut telah divalidasi untuk menjamin kualitas instrumen yang digunakan. Hasil penelitian ini memberikan saran terkait aktivitas pembelajaran yang seharusnya dilakukan oleh pengajar agar sesuai dengan karakteristik berpikir siswa dalam mengonstruksi bukti pada masing-masing kuadran, misalnya : pendekatan heurmenistik, menggunakan metode dua-kolom, pembelajaran worked-example ataupun menggunakan metode terstruktur. Kata Kunci: bukti, pengajaran bukti, mahasiswa, model kuadran

scholarly journals Acute Coronary Syndromes and Inflammatory Bowel Disease: The Gut–Heart Connection

2021 ◽  
Vol 10 (20) ◽  
pp. 4710
Author(s):  
Ayman Jaaouani ◽  
Abdulrahman Ismaiel ◽  
Stefan-Lucian Popa ◽  
Dan L. Dumitrascu
Keyword(s):  
Inflammatory Bowel Disease ◽  
Bowel Disease ◽  
Acute Coronary Syndromes ◽  
Observational Studies ◽  
Common Ground ◽  
Cochrane Library ◽  
Oral Contraceptive Pills ◽  
Increased Risk ◽  
Coronary Syndromes ◽  
Inflammatory Bowel

(1) Background: Inflammatory bowel disease (IBD) induces a process of systemic inflammation, sharing common ground with acute coronary syndromes (ACS). Growing evidence points towards a possible association between IBD and an increased risk of ACS, yet the topic is still inconclusive. Therefore, we conducted a systematic review aiming to clarify these gaps in the evidence. (2) Methods: We conducted a systematic search on EMBASE, Cochrane Library, and PubMed, identifying observational studies published prior to November 2020. The diagnosis of IBD was confirmed via histopathology or codes. Full articles that fulfilled our criteria were included. Quality assessment was performed using the Newcastle–Ottawa scale (NOS). (3) Results: We included twenty observational studies with a total population of ~132 million subjects. Fifteen studies reported a significant association between ACS and IBD, while the remaining five studies reported no increase in ACS risk in IBD patients. (4) Conclusions: ACS risk in IBD patients is related to hospitalizations, acute active flares, periods of active disease, and complications, with a risk reduction during remission. Interestingly, a general increase in ACS risk was reported in younger IBD patients. The role of corticosteroids and oral contraceptive pills in increasing the ACS risk of IBD patients should be investigated.

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