Sound and Fury: McCloskey and Significance Testing in Economics

For about twenty years, Deidre McCloskey has campaigned to convince the economics profession that it is hopelessly confused about statistical significance. She argues that many practices associated with significance testing are bad science and that most economists routinely employ these bad practices: “Though to a child they look like science, with all that really hard math, no science is being done in these and 96 percent of the best empirical economics. . .” (McCloskey 1999). McCloskey’s charges are analyzed and rejected. That statistical significance is not economic significance is a jejune and uncontroversial claim, and there is no convincing evidence that economists systematically mistake the two. Other elements of McCloskey’s analysis of statistical significance are shown to be ill-founded, and her criticisms of practices of economists are found to be based in inaccurate readings and tendentious interpretations of their work. Properly used, significance tests are a valuable tool for assessing signal strength, for assisting in model specification, and for determining causal structure.statistical significance, economic significance, significance testing, regression analysis, econometric methodology, Deirdre McCloskey, Neyman-Pearson testing

Counting on the mental number line to make a move: sensorimotor ('pen') control and numerical processing

Mathematics is often conducted with a writing implement. But is there a relationship between numerical processing and sensorimotor ‘pen’ control? We asked participants to move a stylus so it crossed an unmarked line at a location specified by a symbolic number (1–9), where number colour indicated whether the line ran left–right (‘normal’) or vice versa (‘reversed’). The task could be simplified through the use of a ‘mental number line’ (MNL). Many modern societies use number lines in mathematical education and the brain’s representation of number appears to follow a culturally determined spatial organisation (so better task performance is associated with this culturally normal orientation—the MNL effect). Participants (counter-balanced) completed two consistent blocks of trials, ‘normal’ and ‘reversed’, followed by a mixed block where line direction varied randomly. Experiment 1 established that the MNL effect was robust, and showed that the cognitive load associated with reversing the MNL not only affected response selection but also the actual movement execution (indexed by duration) within the mixed trials. Experiment 2 showed that an individual’s motor abilities predicted performance in the difficult (mixed) condition but not the easier blocks. These results suggest that numerical processing is not isolated from motor capabilities—a finding with applied consequences

IAEA coordinated research project on nuclear data for charged-particle monitor reactions and medical isotope production

An IAEA coordinated research project was launched in December 2012 to establish and improve the nuclear data required to characterise charged-particle monitor reactions and extend data for medical radionuclide production. An international team was assembled to undertake work addressing the requirements for more accurate cross-section data over a wide range of targets and projectiles, undertaken in conjunction with a limited number of measurements and more extensive evaluations of the decay data of specific radionuclides. These studies are nearing completion, and are briefly described below

A Pre-Landing Assessment of Regolith Properties at the InSight Landing Site

This article discusses relevant physical properties of the regolith at the Mars InSight landing site as understood prior to landing of the spacecraft. InSight will land in the northern lowland plains of Mars, close to the equator, where the regolith is estimated to be ≥3--5 m thick. These investigations of physical properties have relied on data collected from Mars orbital measurements, previously collected lander and rover data, results of studies of data and samples from Apollo lunar missions, laboratory measurements on regolith simulants, and theoretical studies. The investigations include changes in properties with depth and temperature. Mechanical properties investigated include density, grain-size distribution, cohesion, and angle of internal friction. Thermophysical properties include thermal inertia, surface emissivity and albedo, thermal conductivity and diffusivity, and specific heat. Regolith elastic properties not only include parameters that control seismic wave velocities in the immediate vicinity of the Insight lander but also coupling of the lander and other potential noise sources to the InSight broadband seismometer. The related properties include Poisson’s ratio, P- and S-wave velocities, Young’s modulus, and seismic attenuation. Finally, mass diffusivity was investigated to estimate gas movements in the regolith driven by atmospheric pressure changes. Physical properties presented here are all to some degree speculative. However, they form a basis for interpretation of the early data to be returned from the InSight mission.Additional co-authors: Nick Teanby and Sharon Keda

2008b): The rhetoric of `Signifying nothing': a rejoinder to Ziliak and McCloskey

For a quarter century, Deirdre McCloskey has pushed the idea that economists should take rhetoric seriously. So, here we would like to take her advice and consider the rhetoric of Ziliak and McCloskey's reply to 'Sound and fury. ' If that old rhetorical device, repetition, were a logically compelling argument, then we would be obligated to concede and withdraw our paper. Alas, it is nothing but the fallacy of argumentum ad nauseam; and, indeed, once the repetition is stripped away it is clear that they give no adequate answer to our key points and that our argument emerges unscathed. Much of their oft repeated points also commit the fallacy of ignoratio elenchi -that is, arguing against a point that was never maintained in the first place. Ziliak and McCloskey write as if we had offered a general defense of existing econometric practice. In fact, we are quite critical of many aspects of econometric practice, but we think that Ziliak and McCloskey are wrong on particular points. They also write as if we were simply channeling their bête noir, R.A. Fisher. We are happy to stipulate, along with one of their heroes, that If only … if only … RAF had been a nicer man, of [sic] he had taken pains to be clearer and less enigmatic, if only he had not been obsessed with ambition and personal bitternesses. If only. But then we might not have had Fisher's magnificent achievements

The Economic Effects of the 1918 Influenza Epidemic

The 1918-19 influenza epidemic killed at least 40 million people worldwide and 675,000 people in the United States, far exceeding the combat deaths experienced by the US in the two World Wars, Korea, and Vietnam combined. Besides its extraordinary virulence, the 1918-19 epidemic was also unique in that a disproportionate number of its victims were men and women ages 15 and 44, giving the age profile of mortality a distinct ‘W’ shape rather than the customary ‘U’ shape, and leading to extremely high death rates in the prime working ages. We examine the impact of this exogenous shock on subsequent economic growth using data on US states for the 1919-30 period. Controlling for numerous factors including initial income, density, urbanization, human capital, climate, the sectoral composition of output, geography, and the legacy of slavery, the results indicate a large and robust positive effect of the influenza epidemic on per capita income growth across states during the 1920s.1918; economic growth; flu; influenza

TWO CENTURIES OF TAXES AND SPENDING: A CAUSAL INVESTIGATION OF THE FEDERAL BUDGET PROCESS

Causal relations between U.S. federal taxation and expenditure are analyzed using an approach based on the invariance of econometric relationships in the face of structural inverventions. Institutional evidence for interventions or changes of regime and econometric tests for structural breaks are used to investigate the relative stability of conditional and marginal probability distributions for each variable. The patterns of stability are the products of the underlying causal order. In keeping with earlier work on the post-World War II period, we find that causal order is not constant in the nineteenth century, but the dominant direction is from taxes to spending.