Simultaneous Conformal Prediction of Missing Outcomes with Propensity Score ϵ\epsilon-Discretization

We study the problem of simultaneous predictive inference on multiple outcomes missing at random. We consider a suite of possible simultaneous coverage properties, conditionally on the missingness pattern and on the -- possibly discretized/binned -- feature values. For data with discrete feature distributions, we develop a procedure which attains feature- and missingness-conditional coverage; and further improve it via pooling its results after partitioning the unobserved outcomes. To handle general continuous feature distributions, we introduce methods based on discretized feature values. To mitigate the issue that feature-discretized data may fail to remain missing at random, we propose propensity score $\epsilon$-discretization. This approach is inspired by the balancing property of the propensity score, namely that the missing data mechanism is independent of the outcome conditional on the propensity [Rosenbaum and Rubin (1983)]. We show that the resulting pro-CP method achieves propensity score discretized feature- and missingness-conditional coverage, when the propensity score is known exactly or is estimated sufficiently accurately. Furthermore, we consider a stronger inferential target, the squared-coverage guarantee, which penalizes the spread of the coverage proportion. We propose methods -- termed pro-CP2 -- to achieve it with similar conditional properties as we have shown for usual coverage. A key novel technical contribution in our results is that propensity score discretization leads to a notion of approximate balancing, which we formalize and characterize precisely. In extensive empirical experiments on simulated data and on a job search intervention dataset, we illustrate that our procedures provide informative prediction sets with valid conditional coverage

Distribution-free inference with hierarchical data

This paper studies distribution-free inference in settings where the data set has a hierarchical structure -- for example, groups of observations, or repeated measurements. In such settings, standard notions of exchangeability may not hold. To address this challenge, a hierarchical form of exchangeability is derived, facilitating extensions of distribution-free methods, including conformal prediction and jackknife+. While the standard theoretical guarantee obtained by the conformal prediction framework is a marginal predictive coverage guarantee, in the special case of independent repeated measurements, it is possible to achieve a stronger form of coverage -- the "second-moment coverage" property -- to provide better control of conditional miscoverage rates, and distribution-free prediction sets that achieve this property are constructed. Simulations illustrate that this guarantee indeed leads to uniformly small conditional miscoverage rates. Empirically, this stronger guarantee comes at the cost of a larger width of the prediction set in scenarios where the fitted model is poorly calibrated, but this cost is very mild in cases where the fitted model is accurate

A good professional reputation is in the eye of the beholder

Reputation is audience-specific, write Gokhan Ertug, Tamar Yogev, Yonghoon Lee and Peter Hedströ

(Main Section: Ecological Planning)

Wetlands are being negatively affected by various human activities such as reclamation, construction of levees, and conventional agricultural activities. Upo Wetland is the largest inland wetland in the Republic of Korea (hereinafter Korea). It has not only been designated as a wetland protection area by the Wetland Conservation Act of Korea but also registered as a Ramsar Site in 1998. In this study, cognitive mapping of the Upo Wetland and surrounding areas was applied to identify sensitive and vulnerable areas that should be carefully managed. The results of the cognitive mapping were compared with existing land-use zones of the wetland conservation area. Furthermore, this paper discusses the advantages of resident participation in cognitive mapping over conventional social and environmental analysis for landscape planning on other conservation areas

Facile Method to Prepare for the Ni2P Nanostructures with Controlled Crystallinity and Morphology as Anode Materials of Lithium-Ion Batteries

Conversion reaction materials (transition metal oxides, sulfides, phosphides, etc.) are attractive in the field of lithium-ion batteries because of their high theoretical capacity and low cost. However, the realization of these materials in lithium-ion batteries is impeded by large voltage hysteresis, high polarization, inferior cycle stability, rate capability, irreversible capacity loss in first cycling, and dramatic volume change during redox reactions. One method to overcome these problems is the introduction of amorphous materials. This work introduces a facile method to synthesize amorphous and crystalline dinickel phosphide (Ni2P) nanoparticle clusters with identical morphology and presents a direct comparison of the two materials as anode materials for rechargeable lithium-ion batteries. To assess the effect of crystallinity and hierarchical structure of nanomaterials, it is crucial to conserve other factors including size, morphology, and ligand of nanoparticles. Although it is rarely studied about synthetic methods of well-controlled Ni2P nanomaterials to meet the above criteria, we synthesized amorphous, crystalline Ni2P, and self-assembled Ni2P nanoparticle clusters via thermal decomposition of nickel-surfactant complex. Interestingly, simple modulation of the quantity of nickel acetylacetonate produced amorphous, crystalline, and self-assembled Ni2P nanoparticles. A 0.357 M nickel-trioctylphosphine (TOP) solution leads to a reaction temperature limitation (similar to 315 degrees C) by the nickel precursor, and crystalline Ni2P (c-Ni2P) nanoparticles clusters are generated. On the contrary, a lower concentration (0.1 M) does not accompany a temperature limitation and hence high reaction temperature (330 degrees C) can be exploited for the self-assembly of Ni2P (s-Ni2P) nanoparticle clusters. Amorphous Ni2P (a-Ni2P) nanoparticle clusters are generated with a high concentration (0.714 M) of nickel-TOP solution and a temperature limitation (similar to 290 degrees C). The a-Ni2P nanoparticle cluster electrode exhibits higher capacities and Coulombic efficiency than the electrode based on c-Ni2P nanoparticle clusters. In addition, the amorphous structure of Ni2P can reduce irreversible capacity and voltage hysteresis upon cycling. The amorphous morphology of Ni2P also improves the rate capability, resulting in superior performance to those of c-Ni2P nanoparticle clusters in terms of electrode performance

The Art of Representation: How Reputation Affects Success with Different Audiences in the Contemporary Art Field

We study the effects of actors audience-specific reputations on their levels of success with different audiences in the same field. Extending recent work that has emphasized the presence of multiple audiences with different concerns, we demonstrate that considering audience specificity leads to an improved understanding of reputation effects. Using data on emerging artists in the field of contemporary art from 2001 to 2010, we investigate the manner in which artists audience-specific reputations affect their subsequent success with two distinct audiences: museums and galleries. Our findings suggest that audience-specific reputations have systematically different effects with respect to success with museums and galleries. Our findings also illuminate the extent to which audience-specific reputations are relevant for emerging research on the contingent effects of reputation. In particular, our findings support our predictions that audiences differ from one another in terms of the extent to which other signals (specifically, status and interaction with other audiences) enhance or reduce the value of audience-specific reputations. Our study thus advances theory by providing empirical evidence for the value of incorporating audience-specific reputations into the general study of reputation.Funding Agencies|Oxford University Centre for Corporate Reputation; European Research Council under the European Union [324233]; Riksbankens Jubileumsfond [DNR M12-0301:1]</p

The Art of Representation: How Reputation Affects Success with Different Audiences in the Contemporary Art Field

We study the effects of actors audience-specific reputations on their levels of success with different audiences in the same field. Extending recent work that has emphasized the presence of multiple audiences with different concerns, we demonstrate that considering audience specificity leads to an improved understanding of reputation effects. Using data on emerging artists in the field of contemporary art from 2001 to 2010, we investigate the manner in which artists audience-specific reputations affect their subsequent success with two distinct audiences: museums and galleries. Our findings suggest that audience-specific reputations have systematically different effects with respect to success with museums and galleries. Our findings also illuminate the extent to which audience-specific reputations are relevant for emerging research on the contingent effects of reputation. In particular, our findings support our predictions that audiences differ from one another in terms of the extent to which other signals (specifically, status and interaction with other audiences) enhance or reduce the value of audience-specific reputations. Our study thus advances theory by providing empirical evidence for the value of incorporating audience-specific reputations into the general study of reputation.Funding Agencies|Oxford University Centre for Corporate Reputation; European Research Council under the European Union [324233]; Riksbankens Jubileumsfond [DNR M12-0301:1]</p