Observing many researchers using the same data and hypothesis reveals a hidden universe of uncertainty

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 team's 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.

The COVID-19 Pandemic and the Rental Market: Evidence From Craigslist

Past research has demonstrated the racially and spatially uneven impacts of economic shocks and environmental disasters on various markets. In this article, we examine if and how the first few months of the COVID-19 pandemic affected the market for rental housing in the 49 largest metropolitan areas in the United States. Using a unique data set of new rental listings gathered from Craigslist and localized measures of the pandemic's severity we find that, from mid-March to early June, local spread of COVID-19 is followed by reduced median and mean rent. However, this trend is driven by dropping rents for listings in Black, Latino, and diverse neighborhoods. Listings in majority White neighborhoods experience rent increases during this time. Our analyses make multiple contributions. First, we add to the burgeoning literature examining the rental market as a key site of perpetuating sociospatial inequality. Second, we demonstrate the utility of data gathered online for analyzing housing. And third, by reflecting on research that shows how past crises have increased sociospatial inequality and up-to-date work showing the racially and spatially unequal effects of the COVID-19 pandemic, we discuss some possible mechanisms by which the pandemic may be affecting the market for rental housing as well as implications for long-term trends.

The Unequal Availability of Rental Housing Information Across Neighborhoods

As more urban residents find their housing through online search tools, recent research has theorized the potential for online information to transform and equalize the housing search process. Yet, very little is known about what rental housing information is available online. Using a corpus of millions of geocoded Craigslist advertisements for rental housing across the 50 largest metropolitan statistical areas in the United States merged with census tract-level data from the American Community Survey, we identify and describe the types of information commonly included in listings across different types of neighborhoods. We find that in the online housing market, renters are exposed to fundamentally different types of information depending on the ethnoracial and socioeconomic makeup of the neighborhoods where they are searching.

Operative vaginal delivery at Port Moresby General Hospital from 1977 to 2010

This paper presents 35 years of history of operative vaginal delivery at the Port Moresby General Hospital (PMGH). From the early 1970s when Dr. G.C. Bird was appointed as Head of Obstetrics at PMGH, vacuum extraction has been the preferred method of assisted vaginal delivery. In the early 1970s, Dr Bird began to experiment with more effective configurations of the then standard metal Malmstrom vacuum extraction cup: the Bird anterior cup was introduced in 1973 and the posterior cup in 1974. These modifications to the vacuum extractor cup allowed for more effective placement of the cup on the flexion point on the fetal head thereby facilitating more successful vacuum-assisted delivery. Between 1977 and 2010 there were a total of 11,458 vacuum extractions (average rate 3.9%) performed, with an average failure rate of 2.5%. During the same period there were 565 vaginal forceps deliveries (rate 0.2%), 11,550 caesarean sections (rate 3.9%) and 182 symphysiotomies (all for failed vacuum extraction procedures) performed. Over the period trends that are noted include a slowly rising caesarean section rate from 2% in the 1970s to nearly 5% in the current decade. Over the same period the assisted vaginal delivery rate has dropped from 10-15% in the 1970s to 3-4% since 2000. The combined fresh stillbirth and early neonatal mortality rate for infants > or = 1.5 kg and > or = 2.5 kg for the period was 11.3/1000 and 9.5/1000 respectively, and compares to a combined fresh stillbirth and early neonatal mortality rate of 8.7/1000 for assisted vaginal delivery.

Rapid estimation of creatinine clearances in patients with liver dysfunction

Different methods are available for rapid assessment of renal function using the patient's serum creatinine concentration and body weight without obtaining urine collection over 24 hr. However, the reliability of these methods in patients with liver diseases has not been established. The purpose of this study was to determine the accuracy and precision of the estimated creatinine clearances obtained by the methods of Cockcroft-Gault, Jelliffe, Mawer, and Siersbaek-Nielsen in patients with liver diseases who have different degrees of renal function. Creatinine clearances obtained from 24-hr urine collection were used as the standard. The different methods for rapid renal function estimation had limited accuracy and reliability in patients with severe liver dysfunction (Child-Pugh class C) and also in those with creatinine clearances of less than 60 ml/min. Creatinine clearances were overestimated by about 40-100%. Using lean body weights, instead of total body weights, reduced the prediction errors. In patients with mild liver dysfunction (Child-Pugh class A), all four estimation methods provided reasonable estimation of the creatinine clearances.

The nitric oxide synthase inhibitor, L-NG-monomethylarginine, reduces carrageenan-induced pleurisy in the rat

Nitric oxide (NO) is a biological mediator that, when produced by the type II (inducible) nitric oxide synthase (NOS), has been implicated in the pathophysiology of inflammatory diseases. To examine this putative role of NO, pleural inflammation was elicited in rats by the intrapleural injection of carrageenan (1 mg). A pleural exudate and cellular influx developed, which peaked at 24 h and generally resolved by 72 h. The cellular influx was primarily composed of polymorphonuclear cells during the first 24 h, followed by macrophages during the subsequent 24 h. Inflammatory cell-associated NOS activity and pleural exudate nitrite (NO2-) + nitrate (NO3-) (NOx) also increased, peaking at 6 h and 24 h, respectively. Cell-associated NOS activity was calcium-independent, indicating the presence of the type II NOS isoform; NOS activity in the pleural cavity and polymorphonuclear cells influx were temporally correlated. Administration of L-NG-monomethylarginine (L-NMA) (200 mg/kg/day) attenuated the pleural exudation, cellular influx, pleural exudate NOx, and cell-associated NOS activity. The relative composition of the pleural cavity cellular infiltrate was not changed by L-NMA, indicating the influx of individual cell types were affected equally. L-Arginine (500 mg/kg/day) completely prevented the effects of L-NMA on pleural exudation and cellular influx and partially prevented the inhibition of pleural exudate NOx accumulation by L-NMA. These data implicate NO as a modulator of the pleural inflammatory response and support a future clinical role for NOS inhibitors in the treatment of inflammatory disease.

Human brain contains a metalloprotease that converts big endothelin-1 to endothelin-1 and is inhibited by phosphoramidon and EDTA

Incubation of big endothelin-1 (bET-1) with protein derived from the detergent-extracted 100,000 g pellet prepared from human brain tissue resulted in the formation of endothelin-1 (ET-1) at a rate of 90 fmol mg-1 protein min-1. This formation was inhibited in a concentration-dependent manner by either phosphoramidon or EDTA, with half-maximal inhibitory concentrations of 2 and 20 microM, respectively. No conversion of big endothelin-3 (bET-3) to endothelin-3 (ET-3) was detected under the same conditions. These results show the presence in the human brain of a metalloprotease-like enzymatic activity which selectively converts bET-1 and ET-1. Together with earlier reports of mRNA for ET-1 this suggests the presence of the entire synthetic pathway for ET-1 in human brain.