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- Breznau, Nate, et al.
(author)
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Observing many researchers using the same data and hypothesis reveals a hidden universe of uncertainty
- 2022
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In: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 119:44
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Journal article (peer-reviewed)abstract
- This study explores how researchers analytical choices affect the reliability of scientific findings. Most discussions of reliability problems in science focus on systematic biases. We broaden the lens to emphasize the idiosyncrasy of conscious and unconscious decisions that researchers make during data analysis. We coordinated 161 researchers in 73 research teams and observed their research decisions as they used the same data to independently test the same prominent social science hypothesis: that greater immigration reduces support for social policies among the public. In this typical case of social science research, research teams reported both widely diverging numerical findings and substantive conclusions despite identical start conditions. Researchers expertise, prior beliefs, and expectations barely predict the wide variation in research outcomes. More than 95% of the total variance in numerical results remains unexplained even after qualitative coding of all identifiable decisions in each teams workflow. This reveals a universe of uncertainty that remains hidden when considering a single study in isolation. The idiosyncratic nature of how researchers results and conclusions varied is a previously underappreciated explanation for why many scientific hypotheses remain contested. These results call for greater epistemic humility and clarity in reporting scientific findings.
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- Mark, Daniel B., et al.
(author)
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Comprehensive Quality-of-Life Outcomes With Invasive Versus Conservative Management of Chronic Coronary Disease in ISCHEMIA
- 2022
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In: Circulation. - : Ovid Technologies (Wolters Kluwer Health). - 0009-7322 .- 1524-4539. ; 145:17, s. 1294-1307
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Journal article (peer-reviewed)abstract
- BACKGROUND: ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches) compared an initial invasive treatment strategy (INV) with an initial conservative strategy in 5179 participants with chronic coronary disease and moderate or severe ischemia. The ISCHEMIA research program included a comprehensive quality-of-life (QOL) substudy.METHODS: In 1819 participants (907 INV, 912 conservative strategy), we collected a battery of disease-specific and generic QOL instruments by structured interviews at baseline; at 3, 12, 24, and 36 months postrandomization; and at study closeout. Assessments included angina-related QOL (19-item Seattle Angina Questionnaire), generic health status (EQ-5D), depressive symptoms (Patient Health Questionnaire-8), and, for North American patients, cardiac functional status (Duke Activity Status Index).RESULTS: Median age was 67 years, 19.2% were female, and 15.9% were non-White. The estimated mean difference for the 19-item Seattle Angina Questionnaire Summary score favored INV (1.4 points [95% CI, 0.2-2.5] over all follow-up). No differences were observed in patients with rare/absent baseline angina (SAQ Angina Frequency score >80). Among patients with more frequent angina at baseline (SAQ Angina Frequency score <80, 744 patients, 41%), those randomly assigned to INV had a mean 3.7-point higher 19-item Seattle Angina Questionnaire Summary score than conservative strategy (95% CI, 1.6-5.8) with consistent effects across SAQ subscales: Physical Limitations 3.2 points (95% CI, 0.2-6.1), Angina Frequency 3.2 points (95% CI, 1.2-5.1), Quality of Life/Health Perceptions 5.3 points (95% CI, 2.8-7.8). For the Duke Activity Status Index, no difference was estimated overall by treatment, but in patients with baseline SAQ Angina Frequency scores <80, Duke Activity Status Index scores were higher for INV (3.2 points [95% CI, 0.6-5.7]), whereas patients with rare/absent baseline angina showed no treatment-related differences. Moderate to severe depression was infrequent at randomization (11.5%-12.8%) and was unaffected by treatment assignment.CONCLUSIONS: In the ISCHEMIA comprehensive QOL substudy, patients with more frequent baseline angina reported greater improvements in the symptom, physical functioning, and psychological well-being dimensions of QOL when treated with an invasive strategy, whereas patients who had rare/absent angina at baseline reported no consistent treatment-related QOL differences.
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| 10. |
- Hochman, A., et al.
(author)
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Dynamics and predictability of cold spells over the Eastern Mediterranean
- 2022
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In: Climate Dynamics. - : Springer Science and Business Media LLC. - 0930-7575 .- 1432-0894. ; 58:7-8, s. 2047-2064
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Journal article (peer-reviewed)abstract
- The accurate prediction of extreme weather events is an important and challenging task, and has typically relied on numerical simulations of the atmosphere. Here, we combine insights from numerical forecasts with recent developments in dynamical systems theory, which describe atmospheric states in terms of their persistence (θ−1) and local dimension (d), and inform on how the atmosphere evolves to and from a given state of interest. These metrics are intuitively linked to the intrinsic predictability of the atmosphere: a highly persistent, low-dimensional state will be more predictable than a low-persistence, high-dimensional one. We argue that θ−1 and d, derived from reanalysis sea level pressure (SLP) and geopotential height (Z500) fields, can provide complementary predictive information for mid-latitude extreme weather events. Specifically, signatures of regional extreme weather events might be reflected in the dynamical systems metrics, even when the actual extreme is not well-simulated in numerical forecasting systems. We focus on cold spells in the Eastern Mediterranean, and particularly those associated with snow cover in Jerusalem. These rare events are systematically associated with Cyprus Lows, which are the dominant rain-bearing weather system in the region. In our analysis, we compare the ‘cold spell Cyprus Lows’ to other ‘regular’ Cyprus Low days. Significant differences are found between cold spells and ‘regular’ Cyprus Lows from a dynamical systems perspective. When considering SLP, the intrinsic predictability of cold spells is lowest hours before the onset of snow. We find that the cyclone’s location, depth and magnitude of air-sea fluxes play an important role in determining its intrinsic predictability. The dynamical systems metrics computed on Z500 display a different temporal evolution to their SLP counterparts, highlighting the different characteristics of the atmospheric flow at the different levels. We conclude that the dynamical systems approach, although sometimes challenging to interpret, can complement conventional numerical forecasts and forecast skill measures, such as model spread and absolute error. This methodology outlines an important avenue for future research, which can potentially be fruitfully applied to other regions and other types of weather extremes.
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