Liability, insurance and defensive medicine: new evidence

For the first time, we test for effects of liability on hospital care using measures of current perceptions of litigation risk at hospital level; in particular, the risk-sharing arrangements agreed between hospitals and their insurers. GMM and ML estimators are used to allow for possible endogeneity of risksharing arrangements. Our findings are consistent with the exercise of liabilityinduced discretion by hospitals, especially regarding use of costly diagnostic imaging. Hospitals facing higher expected litigation costs also use these tests more frequently, after controlling for activity levels, casemix and treatment outcome; the latter indicating that defensive medicine may be present. We also find evidence of fewer new claims against these hospitals, given adverse events, which may indicate the increased use of claims management processes by hospital managers concerned at the expected cost of litigation.Medical malpractice, defensive care, insurance, litigation

The reform of Legal Aid in England and Wales

Legal aid expenditure has risen dramatically in recent years, prompting attention from successive governments. A prominent theme of past and present government reform proposals has been the shifting of risk away from the taxpayer towards lawyers, clients and insurers by altering the means by which legal aid lawyers are paid. This paper explores this theme by presenting information on legal aid expenditure trends over the last two decades and then considering whether payment mechanisms have contributed to this performance. Finally, it reviews previous and current reform proposals in this area. It concludes that, because risk-shifting also alters incentives, it is essential that reform recognises and monitors these.

The Mirage of Triangular Arbitrage in the Spot Foreign Exchange Market

We investigate triangular arbitrage within the spot foreign exchange market using high-frequency executable prices. We show that triangular arbitrage opportunities do exist, but that most have short durations and small magnitudes. We find intra-day variations in the number and length of arbitrage opportunities, with larger numbers of opportunities with shorter mean durations occurring during more liquid hours. We demonstrate further that the number of arbitrage opportunities has decreased in recent years, implying a corresponding increase in pricing efficiency. Using trading simulations, we show that a trader would need to beat other market participants to an unfeasibly large proportion of arbitrage prices to profit from triangular arbitrage over a prolonged period of time. Our results suggest that the foreign exchange market is internally self-consistent and provide a limited verification of market efficiency

Temporal Evolution of Financial Market Correlations

We investigate financial market correlations using random matrix theory and principal component analysis. We use random matrix theory to demonstrate that correlation matrices of asset price changes contain structure that is incompatible with uncorrelated random price changes. We then identify the principal components of these correlation matrices and demonstrate that a small number of components accounts for a large proportion of the variability of the markets that we consider. We then characterize the time-evolving relationships between the different assets by investigating the correlations between the asset price time series and principal components. Using this approach, we uncover notable changes that occurred in financial markets and identify the assets that were significantly affected by these changes. We show in particular that there was an increase in the strength of the relationships between several different markets following the 2007--2008 credit and liquidity crisis.Comment: 15 pages, 10 figures, 1 table. Accepted for publication in Phys. Rev. E. v2 includes additional section

Information and the disposition of medical malpractice claims: A competing risks analysis *

Abstract We explore empirically, using a competing risk model, the relationship between information about case strength and the speed with which medical malpractice disputes are resolved. We have data on the time to resolution of a number of such disputes in a group of English hospitals, as well as the means by which each dispute is resolved (drop, settlement, or trial). In addition we have detailed data on the evolution of expert assessments of case strength, and on the timing of procedural events (i.e. external experts' reports) that are designed to share information and that, therefore, might be expected to influence litigation outcomes. We find that litigation encourages dropping and settling of cases over time in a systematic way relating to their assessed strength; cases that involve relatively little uncertainty are resolved faster than those where liability appears to be more unclear. We suggest that this evidence is consistent with the litigation process using time to help sort, and deal with, cases according to their strength. JEL number: C7, K

How does Europe Make Its Mind Up? Connections, cliques, and compatibility between countries in the Eurovision Song Contest

We investigate the complex relationships between countries in the Eurovision Song Contest, by recasting past voting data in terms of a dynamical network. Despite the British tendency to feel distant from Europe, our analysis shows that the U.K. is remarkably compatible, or 'in tune', with other European countries. Equally surprising is our finding that some other core countries, most notably France, are significantly 'out of tune' with the rest of Europe. In addition, our analysis enables us to confirm a widely-held belief that there are unofficial cliques of countries -- however these cliques are not always the expected ones, nor can their existence be explained solely on the grounds of geographical proximity. The complexity in this system emerges via the group 'self-assessment' process, and in the absence of any central controller. One might therefore speculate that such complexity is representative of many real-world situations in which groups of 'agents' establish their own inter-relationships and hence ultimately decide their own fate. Possible examples include groups of individuals, societies, political groups or even governments

Self-organized global control of carbon emissions

There is much disagreement concerning how best to control global carbon emissions. We explore quantitatively how different control schemes affect the collective emission dynamics of a population of emitting entities. We uncover a complex trade-off which arises between average emissions (affecting the global climate), peak pollution levels (affecting citizens' everyday health), industrial efficiency (affecting the nation's economy), frequency of institutional intervention (affecting governmental costs), common information (affecting trading behavior) and market volatility (affecting financial stability). Our findings predict that a self-organized free-market approach at the level of a sector, state, country or continent, can provide better control than a top-down regulated scheme in terms of market volatility and monthly pollution peaks.Comment: 4 pages, 4 figure

Dynamic communities in multichannel data: An application to the foreign exchange market during the 2007--2008 credit crisis

We study the cluster dynamics of multichannel (multivariate) time series by representing their correlations as time-dependent networks and investigating the evolution of network communities. We employ a node-centric approach that allows us to track the effects of the community evolution on the functional roles of individual nodes without having to track entire communities. As an example, we consider a foreign exchange market network in which each node represents an exchange rate and each edge represents a time-dependent correlation between the rates. We study the period 2005-2008, which includes the recent credit and liquidity crisis. Using dynamical community detection, we find that exchange rates that are strongly attached to their community are persistently grouped with the same set of rates, whereas exchange rates that are important for the transfer of information tend to be positioned on the edges of communities. Our analysis successfully uncovers major trading changes that occurred in the market during the credit crisis.Comment: 8 pages, 6 figures, accepted for publication in Chao