30 research outputs found
Global solutions of a free boundary problem for selfgravitating scalar fields
The weak cosmic censorship hypothesis can be understood as a statement that
there exists a global Cauchy evolution of a selfgravitating system outside an
event horizon. The resulting Cauchy problem has a free null-like inner
boundary. We study a selfgravitating spherically symmetric nonlinear scalar
field. We show the global existence of a spacetime with a null inner boundary
that initially is located outside the Schwarzschild radius or, more generally,
outside an apparent horizon. The global existence of a patch of a spacetime
that is exterior to an event horizon is obtained as a limiting case.Comment: 31 pages, revtex, to appear in the Classical and Quantum Gravit
Justify your alpha
Benjamin et al. proposed changing the conventional “statistical significance” threshold (i.e.,the alpha level) from p ≤ .05 to p ≤ .005 for all novel claims with relatively low prior odds. They provided two arguments for why lowering the significance threshold would “immediately improve the reproducibility of scientific research.” First, a p-value near .05provides weak evidence for the alternative hypothesis. Second, under certain assumptions, an alpha of .05 leads to high false positive report probabilities (FPRP2 ; the probability that a significant finding is a false positive
Same data, different conclusions: Radical dispersion in empirical results when independent analysts operationalize and test the same hypothesis
In this crowdsourced initiative, independent analysts used the same dataset to test two hypotheses regarding the effects of scientists’ gender and professional status on verbosity during group meetings. Not only the analytic approach but also the operationalizations of key variables were left unconstrained and up to individual analysts. For instance, analysts could choose to operationalize status as job title, institutional ranking, citation counts, or some combination. To maximize transparency regarding the process by which analytic choices are made, the analysts used a platform we developed called DataExplained to justify both preferred and rejected analytic paths in real time. Analyses lacking sufficient detail, reproducible code, or with statistical errors were excluded, resulting in 29 analyses in the final sample. Researchers reported radically different analyses and dispersed empirical outcomes, in a number of cases obtaining significant effects in opposite directions for the same research question. A Boba multiverse analysis demonstrates that decisions about how to operationalize variables explain variability in outcomes above and beyond statistical choices (e.g., covariates). Subjective researcher decisions play a critical role in driving the reported empirical results, underscoring the need for open data, systematic robustness checks, and transparency regarding both analytic paths taken and not taken. Implications for organizations and leaders, whose decision making relies in part on scientific findings, consulting reports, and internal analyses by data scientists, are discussed
Living in a country with a strong primary care system is beneficial to people with chronic conditions
In light of the growing pressure that multiple chronic diseases place on health care systems, we investigated whether strong primary care was associated with improved health outcomes for the chronically ill. We did this by combining country- and individual-level data for the twenty-seven countries of the European Union, focusing on people's selfrated health status and whether or not they had severe limitations or untreated conditions. We found that people with chronic conditions were more likely to be in good or very good health in countries that had a stronger primary care structure and better coordination of care. People with more than two chronic conditions benefited most: Their self-rated health was higher if they lived in countries with a stronger primary care structure, better continuity of care, and a more comprehensive package of primary care services. In general, while having access to a strong primary care system mattered for people with chronic conditions, the degree to which it mattered differed across specific subgroups (for example, people with primary care-sensitive conditions) and primary care dimensions. Primary care reforms, therefore, should be person centered, addressing the needs of subgroups of patients while also finding a balance between structure and service delivery