Washington, D.C. : Wynne Associates, [1974]

A. Philip Dawid, Vanessa Didelez

Source: Statist. Surv., Volume 4, 184--231.

Abstract:
We consider the problem of learning about and comparing the consequences of dynamic treatment strategies on the basis of observational data. We formulate this within a probabilistic decision-theoretic framework. Our approach is compared with related work by Robins and others: in particular, we show how Robins’s ‘ G -computation’ algorithm arises naturally from this decision-theoretic perspective. Careful attention is paid to the mathematical and substantive conditions required to justify the use of this formula. These conditions revolve around a property we term stability , which relates the probabilistic behaviours of observational and interventional regimes. We show how an assumption of ‘sequential randomization’ (or ‘no unmeasured confounders’), or an alternative assumption of ‘sequential irrelevance’, can be used to infer stability. Probabilistic influence diagrams are used to simplify manipulations, and their power and limitations are discussed. We compare our approach with alternative formulations based on causal DAGs or potential response models. We aim to show that formulating the problem of assessing dynamic treatment strategies as a problem of decision analysis brings clarity, simplicity and generality.

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Shpitser, I. and Pearl, J. (2006a). Identification of conditional interventional distributions. In Proceedings of the 22nd Annual Conference on Uncertainty in Artificial Intelligence (UAI-06) ( R. Dechter and T. Richardson, eds.). 437–444. AUAI Press, Corvallis, Oregon. http://tinyurl.com/2um8w47

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Spirtes, P., Glymour, C. and Scheines, R. (2000). Causation, Prediction and Search, Second ed. Springer-Verlag, New York.

Sterne, J. A. C., May, M., Costagliola, D., de Wolf, F., Phillips, A. N., Harris, R., Funk, M. J., Geskus, R. B., Gill, J., Dabis, F., Miro, J. M., Justice, A. C., Ledergerber, B., Fatkenheuer, G., Hogg, R. S., D’Arminio-Monforte, A., Saag, M., Smith, C., Staszewski, S., Egger, M., Cole, S. R. and When To Start Consortium (2009). Timing of initiation of antiretroviral therapy in AIDS-Free HIV-1-infected patients: A collaborative analysis of 18 HIV cohort studies. Lancet 373 1352–1363.

Taubman, S. L., Robins, J. M., Mittleman, M. A. and Hernán, M. A. (2009). Intervening on risk factors for coronary heart disease: An application of the parametric g-formula. International Journal of Epidemiology 38 1599–1611.

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Chanmin Kim, Michael J. Daniels, Joseph W. Hogan, Christine Choirat, Corwin M. Zigler.

Source: The Annals of Applied Statistics, Volume 13, Number 3, 1927--1956.

Abstract:
Emission control technologies installed on power plants are a key feature of many air pollution regulations in the US. While such regulations are predicated on the presumed relationships between emissions, ambient air pollution and human health, many of these relationships have never been empirically verified. The goal of this paper is to develop new statistical methods to quantify these relationships. We frame this problem as one of mediation analysis to evaluate the extent to which the effect of a particular control technology on ambient pollution is mediated through causal effects on power plant emissions. Since power plants emit various compounds that contribute to ambient pollution, we develop new methods for multiple intermediate variables that are measured contemporaneously, may interact with one another, and may exhibit joint mediating effects. Specifically, we propose new methods leveraging two related frameworks for causal inference in the presence of mediating variables: principal stratification and causal mediation analysis. We define principal effects based on multiple mediators, and also introduce a new decomposition of the total effect of an intervention on ambient pollution into the natural direct effect and natural indirect effects for all combinations of mediators. Both approaches are anchored to the same observed-data models, which we specify with Bayesian nonparametric techniques. We provide assumptions for estimating principal causal effects, then augment these with an additional assumption required for causal mediation analysis. The two analyses, interpreted in tandem, provide the first empirical investigation of the presumed causal pathways that motivate important air quality regulatory policies.

Jorge A. León.

Source: Bernoulli, Volume 26, Number 3, 2436--2462.

Abstract:
Let $B^{H}$ be a fractional Brownian motion with Hurst parameter $Hin (0,1/2)$ and $p:mathbb{R} ightarrow mathbb{R}$ a polynomial function. The main purpose of this paper is to introduce a Stratonovich type stochastic integral with respect to $B^{H}$, whose domain includes the process $p(B^{H})$. That is, an integral that allows us to integrate $p(B^{H})$ with respect to $B^{H}$, which does not happen with the symmetric integral given by Russo and Vallois ( Probab. Theory Related Fields 97 (1993) 403–421) in general. Towards this end, we combine the approaches utilized by León and Nualart ( Stochastic Process. Appl. 115 (2005) 481–492), and Russo and Vallois ( Probab. Theory Related Fields 97 (1993) 403–421), whose aims are to extend the domain of the divergence operator for Gaussian processes and to define some stochastic integrals, respectively. Then, we study the relation between this Stratonovich integral and the extension of the divergence operator (see León and Nualart ( Stochastic Process. Appl. 115 (2005) 481–492)), an Itô formula and the existence of a unique solution of some Stratonovich stochastic differential equations. These last results have been analyzed by Alòs, León and Nualart ( Taiwanese J. Math. 5 (2001) 609–632), where the Hurst paramert $H$ belongs to the interval $(1/4,1/2)$.

Ilya Pavlyukevich, Georgiy Shevchenko.

Source: Bernoulli, Volume 26, Number 2, 1381--1409.

Abstract:
In this paper, we study the Stratonovich stochastic differential equation $mathrm{d}X=|X|^{alpha }circ mathrm{d}B$, $alpha in (-1,1)$, which has been introduced by Cherstvy et al. ( New J. Phys. 15 (2013) 083039) in the context of analysis of anomalous diffusions in heterogeneous media. We determine its weak and strong solutions, which are homogeneous strong Markov processes spending zero time at $0$: for $alpha in (0,1)$, these solutions have the form egin{equation*}X_{t}^{ heta }=((1-alpha)B_{t}^{ heta })^{1/(1-alpha )},end{equation*} where $B^{ heta }$ is the $ heta $-skew Brownian motion driven by $B$ and starting at $frac{1}{1-alpha }(X_{0})^{1-alpha }$, $ heta in [-1,1]$, and $(x)^{gamma }=|x|^{gamma }operatorname{sign}x$; for $alpha in (-1,0]$, only the case $ heta =0$ is possible. The central part of the paper consists in the proof of the existence of a quadratic covariation $[f(B^{ heta }),B]$ for a locally square integrable function $f$ and is based on the time-reversion technique for Markovian diffusions.

Barack Obama said the “rule of law is at risk” following the justice department’s decision to drop charges against former Trump advisor Mike Flynn, as he issued a stark warning about the long-term impact on the American way of life by his successor.

Roderick J. Little.

Source: Statistical Science, Volume 34, Number 4, 580--583.

Andreas Buja, Lawrence Brown, Richard Berk, Edward George, Emil Pitkin, Mikhail Traskin, Kai Zhang, Linda Zhao.

Source: Statistical Science, Volume 34, Number 4, 523--544.

Abstract:
In the early 1980s, Halbert White inaugurated a “model-robust” form of statistical inference based on the “sandwich estimator” of standard error. This estimator is known to be “heteroskedasticity-consistent,” but it is less well known to be “nonlinearity-consistent” as well. Nonlinearity, however, raises fundamental issues because in its presence regressors are not ancillary, hence cannot be treated as fixed. The consequences are deep: (1) population slopes need to be reinterpreted as statistical functionals obtained from OLS fits to largely arbitrary joint ${x extrm{-}y}$ distributions; (2) the meaning of slope parameters needs to be rethought; (3) the regressor distribution affects the slope parameters; (4) randomness of the regressors becomes a source of sampling variability in slope estimates of order $1/sqrt{N}$; (5) inference needs to be based on model-robust standard errors, including sandwich estimators or the ${x extrm{-}y}$ bootstrap. In theory, model-robust and model-trusting standard errors can deviate by arbitrary magnitudes either way. In practice, significant deviations between them can be detected with a diagnostic test.

Benjamin Meyer
Jul 3, 2019; 39:5326-5335
Systems/Circuits

Speech by Mr Agustín Carstens, General Manager of the BIS, at the Fourteenth ASBA-BCBS-FSI High-level Meeting on Global and Regional Supervisory Priorities, Lima, 1 October 2019.

Once the search has begun, something will be found

We can adapt flexibly to environment changes and search for the most appropriate rule to a context. The orbital prefrontal cortex (PFo) has been associated with decision making, rule generation and maintenance, and more generally has been considered important for behavioral flexibility. To better understand the neural mechanisms underlying the flexible behavior, we studied the ability to generate a switching signal in monkey PFo when a strategy is changed. In the strategy task, we used a visual cue to instruct two male rhesus monkeys either to repeat their most recent choice (i.e., stay strategy) or to change it (i.e., shift strategy). To identify the strategy switching-related signal, we compared nonswitch and switch trials, which cued the same or a different strategy from the previous trial, respectively. We found that the switching-related signal emerged during the cue presentation and it was combined with the strategy signal in a subpopulation of cells. Moreover, the error analysis showed that the activity of the switch-related cells reflected whether the monkeys erroneously switched or not the strategy, rather than what was required for that trial. The function of the switching signal could be to prompt the use of different strategies when older strategies are no longer appropriate, conferring the ability to adapt flexibly to environmental changes. In our task, the switching signal might contribute to the implementation of the strategy cued, overcoming potential interference effects from the strategy previously cued. Our results support the idea that ascribes to PFo an important role for behavioral flexibility.

SIGNIFICANCE STATEMENT We can flexibly adapt our behavior to a changing environment. One of the prefrontal areas traditionally associated with the ability to adapt to new contingencies is the orbital prefrontal cortex (PFo). We analyzed the switching related activity using a strategy task in which two rhesus monkeys were instructed by a visual cue either to repeat or change their most recent choice, respectively using a stay or a shift strategy. We found that PFo neurons were modulated by the strategy switching signal, pointing to the importance of PFo in behavioral flexibility by generating control over the switching of strategies.

Over his five-decade-plus career, the "Strega Nona" author contributed to more than 270 books

"It is unfortunate that it has come to pass that we have to collectively and overtly publicly declare that we are unified," says Alberta Medical Association president Christine Molnar.

Some school travel groups in Cape Breton that had trips cancelled in March due to COVID-19 are still waiting to get their money back.

While traveling in Israel in 1948, Leonard Bernstein wrote a letter to his mother with beautiful illustrations by artist Jossi Stern. In anticipation of Mother's Day weekend, "In the Muse" highlights that digitized letter from the Leonard Bernstein Collection and encourages readers to send illustrated letters of their own.

The European repo market has held up well amid the initial volatility created by the economic slowdown caused by COVID-19,...

The post European Repo Demonstrates Its Resilience appeared first on OpenMarkets.

Documents created by the top disease investigators in the U.S. meant to give step-by-step advice to local leaders deciding when and how to reopen public places such as mass transit, day care centres and restaurants during the still-raging pandemic have been shelved by the Trump administration.

Students in Penn State’s Master of Health Administration program are learning first-hand how the skills and competencies they are acquiring in the classroom will be applied in their professional careers. A recent virtual roundtable event provided opportunities for students to learn real-world strategies from health care industry leaders that are being applied in response to the COVID-19 pandemic.

Repair site iFixit has shared x-ray photographs of the new Magic Keyboard for iPad Pro, and they reveal an accessory more complicated than it might appear from the outside.

An incorrect GPS coordinate leads a worship team to the end of the road, yet God has another route planned.

THE irony that the recent weather would have been ideal for the start of the domestic cricket season is not lost on Kyle Coetzer.

The Dahme-Spreewald administrative district’s local building inspection authority confirmed the completion of the passenger terminal (Terminal 1) at BER following completion of the construction work.

A PUBLIC health professor has warned that the Scottish Government’s strategy to escape the lockdown will encounter “a big problem” unless test results can be provided quicker.

Many parents are having to take on a variety of new roles, from playing IT help desk to becoming makeshift teaching assistants to supervising recess.

Schools and tech companies in the U.S. and abroad have experience deploying virtual learning should a coronavirus emergency arise.

FIVE new nursery extensions being built at schools across Edinburgh have been thrown into doubt after the company building the facilities entered administration.

THE SCOTTISH Government is reviewing its Covid-19 testing strategy after the Deputy First Minster has been left “frustrated” by reports home care workers have been told to travel to the other side of Scotland for tests.

While the Trump administration proposal would not strip student eligibility for Head Start, the federal school lunch program, or the Individual with Disabilities Education Act, it could still affect millions of school-aged children who live with immigrant parents.

A $59 million investment in software developer Social Solutions aims to ease the flow of data among schools and social service providers.

NEIL Mackay (“Johnson? Sturgeon? When it comes to coronavirus they are both the same”, The Herald, May 5) lambasts Nicola Sturgeon and Boris Johnson for both taking an almost identical approach in their fight against Covid-19, somehow implying that this is in itself a fault.

Many parents are having to take on a variety of new roles, from playing IT help desk to becoming makeshift teaching assistants to supervising recess.

A five-part series on mistakes made by school administrators is wrapped-up today with commentaries from Dr. Lynell Powell, Stuart Ablon, Alisha Pollastri, Diane Mora and many comments from readers

William Leou, a 6th grade science teacher at the Brooklyn School for Collaborative Studies, uses an organizational worksheet to help students draw arguments from evidence.

Chris Knutson, an 8th grade history teacher at Horning Middle School in Waukesha, Wis., shares how he incorporates learning conferences into his lessons.

Source: El Periódico - Las políticas climáticas que se centran en la agricultura y los bosques podrían llevar al aumento de los precios de los alimentos, pero reducir la deforestación e incrementar la captura de carbono en la agricultura podría reducir significativamente las emisiones de gases de efecto invernadero, evitando riesgos para la seguridad alimentaria, según un nuevo estudio publicado en 'Environmental Research Letters'.

Intussusception is the most common cause of intestinal obstruction in young children. To date, there have been no prospective studies that have been able to develop a reliable clinical prediction model to determine which patients are at low risk for intussusception.

This study is the largest prospective cohort study to date to evaluate children with possible intussusception. It includes both univariate and multivariate analyses to develop clinical prediction models for patients at low risk for intussusception. (Read the full article)

Although it has been shown that cystic fibrosis newborn screening is beneficial, the strategies vary widely, and there has been uncertainty about the costs and consequences of different algorithms and whether screening methods/decisions should be based on assumed cost differences.

This study contributes by offering a comparison of both costs, assessed comprehensively, and the consequences associated with the 2 most popular screening methodologies, immunoreactive trypsinogen/immunoreactive trypsinogen and immunoreactive trypsinogen/DNA, by using a decision-tree framework allowing variation in the model parameters. (Read the full article)

Existing clinical research policy does not guarantee availability of results. Registration on the Web site ClinicalTrials.gov and the Food and Drug Administration Amendments Act improved transparency in pediatric clinical research. Registration and publication remain voluntary for many trials involving children.

Only 29% of completed registered studies and 53% of National Institutes of Health–funded trials involving children were published. Numbers of studies are increasing. Registration and posting of results on ClinicalTrials.gov should be mandatory for all studies involving children. (Read the full article)