The Effect of State Community Rating Regulations on Premiums and Coverage in the Individual Health Insurance Market

Some states have implemented community rating regulations to limit the extent to which premiums in the individual health insurance market can vary with a person�s health status. Community rating and guaranteed issues laws were passed with hopes of increasing access to affordable insurance for people with high-risk health conditions, but there are concerns that these laws led to adverse selection. In some sense, the extent to which these regulations ultimately affected the individual market depends in large part on the degree of risk segmentation in unregulated states. In this paper, we examine the relationship between expected medical expenses, individual insurance premiums, and the likelihood of obtaining individual insurance using data from both the National Health Interview Survey and the Community Tracking Study Household Survey. We test for differences in these relationships between states with both community rating and guaranteed issue and states with no such regulations. While we find that people living in unregulated states with higher expected expense due to chronic health conditions pay modestly higher premiums and are somewhat less likely to obtain coverage, the variation between premiums and risk in unregulated individual insurance markets is far from proportional; there is considerable pooling. In regulated states, we find that there is no effect of having higher expected expense due to chronic health conditions on neither premiums nor coverage. Overall, our results suggest that the effect of regulation is to produce a slight increase in the proportion uninsured, as increases in low risk uninsureds more than offset decreases in high risk uninsureds. Community rating and guaranteed issue regulations produce only small changes in risk pooling because the extent of pooling in the absence of regulation is substantial.

Screening of Coulomb interactions in transition metals

We discuss different methods of calculation of the screened Coulomb interaction $U$ in transition metals and compare the constraint local-density approximation (LDA) with the GW approach. We clarify that they offer complementary methods of treating the screening and should serve for different purposes. In the GW method, the renormalization of bare on-site Coulomb interactions between 3d electrons occurs mainly through the screening by the same 3d electrons, treated in the random phase approximation (RPA). The basic difference of the constraint-LDA method is that it deals with the neutral processes, where the Coulomb interactions are additionally screened by the ``excited'' electron, since it continues to stay in the system. This is the main channel of screening by the itinerant ($4sp$) electrons, which is especially strong in the case of transition metals and missing in the GW approach, although the details of this screening may be affected by additional approximations, which typically supplement these two methods. The major drawback of the conventional constraint-LDA method is that it does not allow to treat the energy-dependence of $U$. We propose a promising approximation based on the combination of these two methods. First, we take into account the screening of Coulomb interactions in the 3d-electron-line bands located near the Fermi level by the states from the subspace being orthogonal to these bands, using the constraint-LDA methods. The obtained interactions are further renormalized within the bands near the Fermi level in RPA. This allows the energy-dependent screening by electrons near the Fermi level including the same 3d electrons.Comment: 25 pages, 5 figures, 2 table

Health Insurance on the Internet and the Economics of Search

This paper explores the level and dispersion of premiums paid for individual health insurance by comparing asking price' data posted on an electronic insurance exchange with survey data on premiums actually paid in the period just before the advent of electronic exchanges. The primary theoretical question is whether the pattern of differences between asking prices and transactions prices can be explained using a simple search theory. We hypothesize, following suggestions of Stigler and Rothschild, that higher risks who expect to pay higher premiums for a given policy will engage in more intensive search than lower risks, given the same distribution of asking prices. As a result, for a given distribution of asking prices, the dispersion of premiums actually paid (transactions prices) will be smaller for higher risks. Therefore, the introduction of an electronic exchange should have a larger potential influence on the dispersion and level of premiums paid for lower risks than for higher risks. We find evidence consistent with each of these hypotheses.

Study of a pair of coupled continuum equations modeling surface growth

In this communication we introduce a pair of coupled continuum equations to model overlayer growth with evaporation-accretion due to thermal or mechanical agitations of the substrate. We gain insight into the dynamics of growth via one-loop perturbative techniques. This allows us to analyze our numerical data. We conclude that there is a crossover behaviour from a roughening regime to a very long-time, large length scale smoothening regime.Comment: 21 pages, 13 figures. Submitted to J. Phys.: Condens. Matte

Binge drinking: a confused concept and its contemporary history

Binge drinking is a matter of current social, political and media concern. It has a long-term, but also a recent, history. This paper discusses the contemporary history of the concept of binge drinking. In recent years there have been significant changes in how binge drinking is defined and conceptualised. Going on a ‘binge’ used to mean an extended period (days) of heavy drinking, while now it generally refers to a single drinking session leading to intoxication. We argue that the definitional change is related to the shifts in the focus of alcohol policy and alcohol science, in particular in the last two decades, and also in the role of the dominant interest groups. The paper is a case study in the relationship between science and policy. We explore key themes, raise questions and point to a possible agenda for future research

The normalisation of binge drinking? An historical and cross cultural investigation with implications for action

Binge drinking is a matter of current social, media and political concern, rarely out of the headlines and a focus of policy activity. Discussion of binge drinking has focussed on the activities of young people and it is believed to have resulted in significant harm to individuals and to communities. Binge drinking is sometimes portrayed as a recent phenomenon but it has a history and concern about it is not new. This project aimed to set the phenomenon of binge drinking in its historical cultural and contemporary context by considering: historical and anthropological perspectives; the definition and measurement of binge drinking; the contemporary situation in cross national perspective. The overall aim is to draw lessons for policy through the interaction of social science and historical perspectives

Calculations of exchange interaction in impurity band of two-dimensional semiconductors with out of plane impurities

We calculate the singlet-triplet splitting for a couple of two-dimensional electrons in the potential of two positively charged impurities which are located out of plane. We consider different relations between vertical distances of impurities $h_1$ and $h_2$ and their lateral distance $R$. Such a system has never been studied in atomic physics but the methods, worked out for regular two-atomic molecules and helium atom, have been found to be useful. Analytical expressions for several different limiting configurations of impurities are obtained an interpolated formula for intermediate range of parameters is proposed. The $R$-dependence of the splitting is shown to become weaker with increasing $h_1,h_2$.Comment: 14 pages, RevTeX, 5 figures. Submitted to Phys Rev.

First-principle Wannier functions and effective lattice fermion models for narrow-band compounds

We propose a systematic procedure for constructing effective lattice fermion models for narrow-band compounds on the basis of first-principles electronic structure calculations. The method is illustrated for the series of transition-metal (TM) oxides: SrVO$_3$, YTiO$_3$, V$_2$O$_3$, and Y$_2$Mo$_2$O$_7$. It consists of three parts, starting from LDA. (i) construction of the kinetic energy Hamiltonian using downfolding method. (ii) solution of an inverse problem and construction of the Wannier functions (WFs) for the given kinetic energy Hamiltonian. (iii) calculation of screened Coulomb interactions in the basis of \textit{auxiliary} WFs, for which the kinetic-energy term is set to be zero. The last step is necessary in order to avoid the double counting of the kinetic-energy term, which is included explicitly into the model. The screened Coulomb interactions are calculated in a hybrid scheme. First, we evaluate the screening caused by the change of occupation numbers and the relaxation of the LMTO basis functions, using the conventional constraint-LDA approach, where all matrix elements of hybridization involving the TM $d$ orbitals are set to be zero. Then, we switch on the hybridization and evaluate the screening associated with the change of this hybridization in RPA. The second channel of screening is very important, and results in a relatively small value of the effective Coulomb interaction for isolated $t_{2g}$ bands. We discuss details of this screening and consider its band-filling dependence, frequency dependence, influence of the lattice distortion, proximity of other bands, and the dimensionality of the model Hamiltonian.Comment: 35 pages, 25 figure

Anisotropic dynamics of a vicinal surface under the meandering step instability

We investigate the nonlinear evolution of the Bales-Zangwill instability, responsible for the meandering of atomic steps on a growing vicinal surface. We develop an asymptotic method to derive, in the continuous limit, an evolution equation for the two-dimensional step flow. The dynamics of the crystal surface is greatly influenced by the anisotropy inherent to its geometry, and is characterized by the coarsening of undulations along the step direction and by the elastic relaxation in the mean slope direction. We demonstrate, using similarity arguments, that the coalescence of meanders and the step flow follow simple scaling laws, and deduce the exponents of the characteristic length scales and height amplitude. The relevance of these results to experiments is discussed.Comment: 10 pages, 7 figures; submitted to Phys. Rev.