An Alternative Definition of Market Efficiency and some Comments on its Empirical Testing

An alternative definition for market efficiency, based on econometric rather than financial arguments is suggested. It is argued that this new definition, though equivalent to the existing one, has some comparative advantages. Moreover, the conditions under which the results from the application of some commonly used methods for the empirical testing of market efficiency are meaningful are examined, and guidelines for practitioners are suggested. Further, market efficiency is examined in a time-varying risk framework.Market efficiency; Return predictability; Serial correlation in stock returns; Market efficiency in the presence of conditional heteroscedasticity

Decomposing the predictive performance of the moving average trading rule of technical analysis: the contribution of linear and non linear dependencies in stock returns

On several occasions technical analysis rules have been shown to have predictive power. The main purpose of this work is to decompose the predictive power of the moving average trading rule and isolate the portion that could be attributed to the possible exploitation of linear and non linear dependencies in stock returns. Data for the General Index of the Athens Stock Exchange are filtered using linear filters so that the resulting simulated “returns” exhibit no serial correlation. Applying moving average trading rules to both the original and the simulated indices and using a statistical testing procedure that takes into account the sensitivity of the performance of the trading rule as a function of moving average length, it is found that the predictive power of the trading rule is clearly weakened when applied to the simulated index indicating that a substantial part of the rule’s predictive power is due to the exploitation of linear dependencies in stock returns. It is also found that the contribution of linear dependencies in stock returns to the performance of the trading rule is increased for shorter moving average lengths.Market Efficiency; Technical Analysis; Moving Average Trading Rules; Athens Stock Exchange.

A Note on the Use of Moving Average Trading Rules to Test For Weak from Efficiency in Capital Markets

This work focuses on the sensitivity of the performance of the moving average (MA) trading rule of technical analysis to changes in the MA length employed. Empirical analysis of daily data from NYSE, the Vienna Stock Exchange (VSE) and the Athens Stock Exchange (ASE) reveal high variability of the performance of the MA trading rule as a function of the MA length for all these markets, a result that weakens the conclusions of previous works, regarding the validity of the hypothesis of weak form market efficiency. Further, the trading rule is found to have predictive power in ASE and VSE, but not in NYSE.Efficiency of Capital Markets; Technical Analysis Trading Rules with Moving Averages; Athens Stock Exchange; New York Stock Exchange; Vienna Stock Exchange.

Democratic Constraints and Adherence to the Classical Gold Standard

We study how domestic politics affected the decisions of countries to adhere to the classical gold standard. Using a variety of econometric techniques and controlling for a wide range of economic factors, we demonstrate that political constraints were important in the decision of countries to adopt the gold standard as well as in the decision to suspend it. Specifically we find that the probability of adherence to the gold standard was ceteris paribus lower for countries in which domestic politics were organized in a more open and democratic fashion. This effect appears to be driven largely by the extent of domestic political competition and was particularly relevant for peripheral countries

Growing social value polarisation harms economic development

Greater polarisation impedes collective action and is associated with lower levels of GDP per capita, write Sjoerd Beugelsdijk, Mariko J. Klasing and Petros Milioni

The International Epidemiological Transition and the Education Gender Gap

We explore the impact of the international epidemiological transition on educational outcomes of males and females over the second half of the 20th century. We provide strong evidence that the large resulting declines in mortality rates from infectious diseases gave rise to differential life expectancy gains across genders, with females benefiting mostly from them due to their greater responsiveness to vaccination. We also document that these gender differences in life expectancy gains are subsequently reflected in similar differential increases in educational outcomes for males and females. Using an instrumental variables strategy that exploits pre-intervention variation in mortality rates across different infectious diseases we confirm the causal nature of these effects and show that the magnitude of the effects account for a large share of the reduction in the education gender gap that emerged over this period

Aseptic meningoencephalitis mimicking transient ischaemic attacks

Purpose: To highlight meningoencephalitis as a transient ischaemic attack (TIA) mimic and suggest clinical clues for differential diagnosis. Methods: This was an observational study of consecutively admitted patients over a 9.75-year period presenting as TIAs at a stroke unit. Results: A total of 790 patients with TIAs and seven with TIA-like symptoms but a final diagnosis of viral meningoencephalitis were recognised. The most frequent presentations of meningoencephalitis patients were acute sensory hemisyndrome (6) and cognitive deficits (5). Signs of meningeal irritation were minor or absent on presentation. Predominantly lymphocytic pleocytosis, hyperproteinorachia and a normal cerebrospinal fluid (CSF)/serum glucose index (in 5 out of 6 documented patients) were present. Meningeal thickening on a brain magnetic resonance imaging (MRI) scan was the only abnormal imaging finding. Six patients received initial vascular treatment; one thrombolysed. Finally, six patients were treated with antivirals and/or antibiotics. Although neither bacterial nor viral agents were identified on extensive testing, viral meningoencephalitis was the best explanation for all clinical and laboratory findings. Conclusions: Aseptic meningoencephalitis should be part of the differential diagnosis in patients presenting as TIA. The threshold for a lumbar puncture in such patients should be set individually and take into account the presence of mild meningeal symptoms, age and other risk factors for vascular disease, the results of brain imaging and the basic diagnostic work-up for a stroke sourc

Small-vessel occlusion versus large-artery atherosclerotic strokes in diabetics: Patient characteristics, outcomes, and predictors of stroke mechanism

Peer reviewe

Risk, Cooperation and the Economic origins of social Trust: an empirical Investigation

Extensive research has documented the importance of social trust for economic development, yet the origins of trust remain largely unexplored. This paper examines the historical relationship between risk, cooperation and the emergence of social trust. I hypothesize that norms of trust developed in preindustrial times as a result of experiences of collective action and mutual insurance triggered by the need for subsistence farmers to cope with climatic risk. These norms persisted over time, even after climate had become largely unimportant for economic activity. I test this hypothesis in the context of Europe combining high-resolution climate data for the period 1500-2000 with contemporary survey data at the sub-national level. I find that regions characterized by higher year-to-year variability in precipitation and temperature display higher levels of trust. Consistent with a theory of insurance through geographic differentiation, I also find that trust is higher in regions with more spatially heterogeneous precipitation. Furthermore, variation in social trust is driven by weather patterns during the growing season and by historical rather than recent variability. These results are robust to the inclusion of country fixed-effects, a variety of geographical controls, and regional measures of early political and economic development