SciCombinator

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Concept: The Lancet

222

What are the statistical practices of articles published in journals with a high impact factor? Are there differences compared with articles published in journals with a somewhat lower impact factor that have adopted editorial policies to reduce the impact of limitations of Null Hypothesis Significance Testing? To investigate these questions, the current study analyzed all articles related to psychological, neuropsychological and medical issues, published in 2011 in four journals with high impact factors: Science, Nature, The New England Journal of Medicine and The Lancet, and three journals with relatively lower impact factors: Neuropsychology, Journal of Experimental Psychology-Applied and the American Journal of Public Health. Results show that Null Hypothesis Significance Testing without any use of confidence intervals, effect size, prospective power and model estimation, is the prevalent statistical practice used in articles published in Nature, 89%, followed by articles published in Science, 42%. By contrast, in all other journals, both with high and lower impact factors, most articles report confidence intervals and/or effect size measures. We interpreted these differences as consequences of the editorial policies adopted by the journal editors, which are probably the most effective means to improve the statistical practices in journals with high or low impact factors.

Concepts: Statistics, Statistical significance, Ronald Fisher, Statistical hypothesis testing, Effect size, Impact factor, Statistical power, The Lancet

27

We sought to evaluate the characteristics and publication fate of improperly registered clinical trials submitted to a medical journal (The BMJ) over a 4-year period to identify common types of registration issues and their relation to publication outcomes.

Concepts: Health care, Clinical trial, Avicenna, ClinicalTrials.gov, The Lancet, Medical journal, BMJ

14

Maternal undernutrition contributes to 800 000 neonatal deaths annually; stunting, wasting, and micronutrient deficiencies are estimated to underlie nearly 3·1 million child deaths annually. Progress has been made with many interventions implemented at scale and the evidence for effectiveness of nutrition interventions and delivery strategies has grown since The Lancet Series on Maternal and Child Undernutrition in 2008. We did a comprehensive update of interventions to address undernutrition and micronutrient deficiencies in women and children and used standard methods to assess emerging new evidence for delivery platforms. We modelled the effect on lives saved and cost of these interventions in the 34 countries that have 90% of the world’s children with stunted growth. We also examined the effect of various delivery platforms and delivery options using community health workers to engage poor populations and promote behaviour change, access and uptake of interventions. Our analysis suggests the current total of deaths in children younger than 5 years can be reduced by 15% if populations can access ten evidence-based nutrition interventions at 90% coverage. Accelerated gains are possible and about a fifth of the existing burden of stunting can be averted using these approaches, if access is improved in this way. The estimated total additional annual cost involved for scaling up access to these ten direct nutrition interventions in the 34 focus countries is Int$9·6 billion per year. Continued investments in nutrition-specific interventions to avert maternal and child undernutrition and micronutrient deficiencies through community engagement and delivery strategies that can reach poor segments of the population at greatest risk can make a great difference. If this improved access is linked to nutrition-sensitive approaches-ie, women’s empowerment, agriculture, food systems, education, employment, social protection, and safety nets-they can greatly accelerate progress in countries with the highest burden of maternal and child undernutrition and mortality.

Concepts: Nutrition, Poverty, Demography, Child, Acceleration, Micronutrient, Engagement, The Lancet

11

To analyse the total number of newspaper articles citing the four leading general medical journals and to describe national citation patterns.

Concepts: The Lancet, Medical journal, Medical journals

8

INTRODUCTION: In 2001, a Cochrane review of mammography screening questioned whether screening reduces breast cancer mortality, and a more comprehensive review in Lancet, also in 2001, reported considerable overdiagnosis and overtreatment. This led to a heated debate and a recent review of the evidence by UK experts intended to be independent. OBJECTIVE: To explore if general medical and specialty journals differed in accepting the results and methods of three Cochrane reviews on mammography screening. METHODS: We identified articles citing the Lancet review from 2001 or updated versions of the Cochrane review (last search 20 April 2012). We explored which results were quoted, whether the methods and results were accepted (explicit agreement or quoted without caveats), differences between general and specialty journals, and change over time. RESULTS: We included 171 articles. The results for overdiagnosis were not quoted in 87% (148/171) of included articles and the results for breast cancer mortality were not quoted in 53% (91/171) of articles. 11% (7/63) of articles in general medical journals accepted the results for overdiagnosis compared with 3% (3/108) in specialty journals (p=0.05). 14% (9/63) of articles in general medical journals accepted the methods of the review compared with 1% (1/108) in specialty journals (p=0.001). Specialty journals were more likely to explicitly reject the estimated effect on breast cancer mortality 26% (28/108), compared with 8% (5/63) in general medical journals, p=0.02. CONCLUSIONS: Articles in specialty journals were more likely to explicitly reject results from the Cochrane reviews, and less likely to accept the results and methods, than articles in general medical journals. Several specialty journals are published by interest groups and some authors have vested interests in mammography screening.

Concepts: Cancer, Breast cancer, Cochrane Library, Breast, The Lancet, Medical journal

7

The Commission on Investing in Health (CIH), an international group of 25 economists and global health experts, published its Global Health 2035 report in The Lancet in December 2013. The report laid out an ambitious investment framework for achieving a “grand convergence” in health-a universal reduction in deaths from infectious diseases and maternal and child health conditions-within a generation. This article captures ten key elements that the CIH found important to its process and successful outcomes. The elements are presented in chronological order, from inception to post-publication activities. The starting point is to identify the gap that a new commission could help to narrow. A critical early step is to choose a chair who can help to set the agenda, motivate the commissioners, frame the commission’s analytic work, and run the commission meetings in an effective way. In selecting commissioners, important considerations are their technical expertise, ensuring diversity of people and viewpoints, and the connections that commissioners have with the intended policy audience. Financial and human resources need to be secured, typically from universities, foundations, and development agencies. It is important to set a clear end date, so that the commission’s work program, the timing of its meetings and its interim deadlines can be established. In-person meetings are usually a more effective mechanism than conference calls for gaining commissioners' inputs, surfacing important debates, and ‘reality testing’ the commission’s key findings and messages. To have policy impact, the commission report should ideally say something new and unexpected and should have simple messages. Generating new empirical data and including forward-looking recommendations can also help galvanize policy action. Finally, the lifespan of a commission can be extended if it lays the foundation for a research agenda that is then taken up after the commission report is published.

Concepts: The Lancet, Journal of the American Medical Association

5

No systematic review has previously been carried out on randomised controlled trials (RCTs) of veterinary homeopathy in which the control group was an intervention other than placebo (OTP). For eligible peer-reviewed RCTs, the objectives of this study were to assess the risk of bias (RoB) and to quantify the effect size of homeopathic intervention compared with an active comparator or with no treatment.

Concepts: Scientific method, Medicine, Randomized controlled trial, Placebo, Alternative medicine, Homeopathy, The Lancet

5

The accuracy of published medical research is critical for scientists, physicians and patients who rely on these results. However, the fundamental belief in the medical literature was called into serious question by a paper suggesting that most published medical research is false. Here we adapt estimation methods from the genomics community to the problem of estimating the rate of false discoveries in the medical literature using reported $P$-values as the data. We then collect $P$-values from the abstracts of all 77 430 papers published in The Lancet, The Journal of the American Medical Association, The New England Journal of Medicine, The British Medical Journal, and The American Journal of Epidemiology between 2000 and 2010. Among these papers, we found 5322 reported $P$-values. We estimate that the overall rate of false discoveries among reported results is 14% (s.d. 1%), contrary to previous claims. We also found that there is no a significant increase in the estimated rate of reported false discovery results over time (0.5% more false positives (FP) per year, $P = 0.18$) or with respect to journal submissions (0.5% more FP per 100 submissions, $P = 0.12$). Statistical analysis must allow for false discoveries in order to make claims on the basis of noisy data. But our analysis suggests that the medical literature remains a reliable record of scientific progress.

Concepts: Statistics, Mathematics, Approximation, Estimation, The Lancet, Medical journal, BMJ, Journal of the American Medical Association

4

Controversy has surrounded MMR vaccination in the aftermath of Wakefield’s 1998 paper suggesting links between MMR and the development of pervasive developmental disorder in children. The paper sparked off media debate and contributed to a lack of parental trust in health-care providers and reduction in MMR uptake. This review aims to identify and evaluate research on the subject, with a view to present the reasons behind, and influences on parental decision-making in relation to MMR.

Concepts: Psychology, Pervasive developmental disorder, Subject, Developmental psychology, Human development, MMR vaccine, The Lancet, MMR vaccine controversy

3

Since the first study published in the Lancet in 1976, structural neuroimaging has been used in psychosis with the promise of imminent clinical utility. The actual impact of structural neuroimaging in psychosis is still unclear.

Concepts: Impact factor, The Lancet, Journal of the American Medical Association