Modelling Electricity Prices: International Evidence*

This article analyses the evolution of electricity prices in deregulated markets. We present a general class of models that simultaneously takes into account several factors: seasonality, mean reversion, GARCH behaviour and time‐dependent jumps. The models are applied to daily equilibrium spot prices of eight electricity markets. Eight different nested models were estimated to compare the relative importance of each factor in each of the eight markets. We find strong evidence that electricity equilibrium prices are mean‐reverting, with volatility clustering (GARCH) and with jumps of time‐dependent intensity, even after adjusting for seasonality.     

Industry Structure and Corporate Debt Maturity

We examine how industry competition affects firms’ choice of short‐term debt. We find that the percentage of short‐term debt is positively related to industry concentration at low levels of concentration, and inversely related to industry concentration at higher levels of concentration. This nonlinear relation is stronger in industries where firms are either more homogeneous or compete more aggressively. Moreover, we find that firms with shorter‐maturity debt are less aggressive than their rivals in the product market. The overall evidence suggests that although financial contracts alleviate agency problems, they exacerbate the risk of predation.     

Large-scale mortality shocks and the Great Irish Famine 1845–1852

This paper considers the consequences of a large scale mortality shock arising from a famine or epidemic for long run economic and demographic development. The Great Irish Famine of 1845–1852 is taken as a case-study and is incorporated as an exogenous mortality shock into the type of long-run unified growth theory pioneered by Galor and Weil (1999, 2000), and modelled by Lagerlöf (2003a,b) among others. Through calibration, the impact of such a mortality shock occurring on the cusp of a country's transition from a Malthusian to a Modern Growth regime is then depicted.     

Economic importance and statistical significance: Guidelines for communicating empirical research

Abstract

A critical objective for many empirical studies is a thorough evaluation of both substantive importance and statistical significance. Feminist economists have critiqued neoclassical economics studies for an excessive focus on statistical machinery at the expense of substantive issues. Drawing from the ongoing debate about the rhetoric of economic inquiry and significance tests, this paper examines approaches for presenting empirical results effectively to ensure that the analysis is accurate, meaningful, and relevant for the conceptual and empirical context. To that end, it demonstrates several measurement issues that affect the interpretation of economic significance and are commonly overlooked in empirical studies. This paper provides guidelines for clearly communicating two distinct aspects of “significance” in empirical research, using prose, tables, and charts based on OLS, logit, and probit regression results. These guidelines are illustrated with samples of ineffective writing annotated to show weaknesses, followed by concrete examples and explanations of improved presentation.     

Trading frequency and volatility clustering

Volatility clustering, with autocorrelations of the hyperbolic decay rate, is unquestionably one of the most important stylized facts of financial time series. This paper presents a market microstructure model that is able to generate volatility clustering with hyperbolically decaying autocorrelations via traders with multiple trading frequencies, using Bayesian information updates in an incomplete market. The model illustrates that signal extraction, which is induced by multiple trading frequencies, can increase the persistence of the volatility of returns. Furthermore, we show that the volatility of the underlying time series of returns varies greatly with the number of traders in the market.     

A Comparison of EPI Sampling, Probability Sampling, and Compact Segment Sampling Methods for Micro and Small Enterprises

Finding an efficient method for sampling micro- and small-enterprises (MSEs) for research and statistical reporting purposes is a challenge in developing countries, where registries of MSEs are often nonexistent or outdated. This lack of a sampling frame creates an obstacle in finding a representative sample of MSEs. This study uses computer simulations to draw samples from a census of businesses and non-businesses in the Tshwane Municipality of South Africa, using three different sampling methods: the traditional probability sampling method, the compact segment sampling method, and the World Health Organization's Expanded Programme on Immunization (EPI) sampling method. Three mechanisms by which the methods could differ are tested, the proximity selection of respondents, the at-home selection of respondents, and the use of inaccurate probability weights. The results highlight the importance of revisits and accurate probability weights, but the lesser effect of proximity selection on the samples' statistical properties.     

Jumps and betas: A new framework for disentangling and estimating systematic risks

We provide a new theoretical framework for disentangling and estimating the sensitivity towards systematic diffusive and jump risks in the context of factor models. Our estimates of the sensitivities towards systematic risks, or betas, are based on the notion of increasingly finer sampled returns over fixed time intervals. We show consistency and derive the asymptotic distributions of our estimators. In an empirical application of the new procedures involving high-frequency data for forty individual stocks, we find that the estimated monthly diffusive and jump betas with respect to an aggregate market portfolio differ substantially for some of the stocks in the sample.     

Stuck on gold: Real exchange rate volatility and the rise and fall of the gold standard, 1875-1939

Did the gold standard diminish macroeconomic volatility? Supporters thought so, critics thought not, and theory offers ambiguous messages. Hard regimes like the gold standard limit monetary shocks by tying policymakers' hands; but exchange-rate inflexibility compromises shock absorption in a world of real disturbances and nominal stickiness. A model shows how lack of flexibility affects the transmission of terms-of-trade shocks. Evidence from the late nineteenth and early twentieth century exposes a dramatic change. The classical gold standard did absorb shocks, but the interwar gold standard did not, supporting the view that the interwar gold standard was a poor regime choice.     

农网10 kV配电线路拉线坑的定位计算

目前，农网完善工程中的10kV配电线路的施工过程要求，拉线与杆塔的夹角必须符合设计要求，从而保证在不同地形架设的架空线路杆塔稳定。对此，文章提出相应的拉线坑定位计算简易方法。     

Does Monetary Policy Have Asymmetric Effects on Stock Returns?

This paper investigates whether monetary policy has asymmetric effects on stock returns using Markov-switching models. Different measures of a monetary policy stance are adopted. Empirical evidence from monthly returns on the Standard & Poor's 500 price index suggests that monetary policy has larger effects on stock returns in bear markets. Furthermore, it is shown that a contractionary monetary policy leads to a higher probability of switching to the bear-market regime.