Purchasing power parity over two centuries: trends and nonlinearity

In two recent contributions Lothian and Taylor, and Cuddington and Liang, produced empirical evidence that annual data for the dollar-sterling real exchange rate spanning two centuries exhibited a non-linear deterministic trend. This trend could be proxying Harrod-Balassa-Samuelson effects. Lothian and Taylor showed that a linear stationary autoregressive mode, which embodied a cubic trend, implied much faster mean reversion of the real exchange rate to shocks than a model that excluded the trend. This article shows that both non-linearity and a deterministic trend can be allowed for in a theoretically appealing manner and that the fitted models provide a parsimonious explanation of both the dollar-sterling and franc-sterling real exchange rates over the two centuries of data. Generalized impulse response function analysis of the models demonstrates that the speed of adjustment to shocks can be even faster when trends are considered.     

Dynamic almost ideal demand systems: an empirical analysis of alcohol expenditure in Ireland

This paper presents a dynamic form of the Almost Ideal Demand System (AIDS). Three versions of the static AIDS model are employed to determine the preferred long-run equilibrium model and represents the short-run dynamics by an error correction mechanism. This estimation procedure is then applied to alcohol expenditure in Ireland. The estimated point elasticities are consistent with previous studies and a priori expectations. Beer and spirits are found to be price inelastic in both the short and long run. While wine is price inelastic in the short run and price elastic in the long run.     

The effect of robust growth on poverty: a nonlinear analysis

Previous research has shown that economic growth should help to reduce the rate of poverty. However, a number of recent studies have found that the economic expansion of the 1980s had no statistically significant effect on aggregate poverty. It is shown that both a Threshold regression and a Fourier approximation provide a better empirical model of poverty than the standard linear model. It is noteworthy that the nonlinear specifications show a large and significant effect on poverty of the 1980s expansion.     

Why do diners tip: rule-of-thumb or valuation of service?

When diners decide how much to tip, is the decision based on social convention or on conscientious appraisal of server productivity? Previous researchers in economics and social psychology are generally inconclusive on this question. A common finding in the literature is that tip size and service quality are unrelated, a result usually obtained from OLS regressions. OLS is only appropriate if service quality is exogenous. It is argued that service quality is very likely endogenous in any regression of tip size; good quality encourages good tips, but server expectations of good tips encourage good quality. This simultaneity is accounted for by jointly estimating percentage tips and customer rankings of service quality on a sample of 247 diners in a Central Minnesota restaurant. Included are explanatory variables consistent with both the social psychology and economic views of tipping. In contrast to previous studies, it is found that service quality significantly affects tip size and when servers expect higher tips, customers rank service quality higher. Also it is found that patronage frequency and coupon redemption have no effect on percentage tips, but server gender influences quality significantly. It is concluded that the results are generally supportive of an economic hypothesis of tipping.     

Prequential analysis of stock market returns

The Brier score and a covariance partition due to Yates are considered to study the probabilistic forecasts of a vector autoregression on stock market returns. Probabilistic forecasts from a model and data developed by Campbell (1991 Campbell, JY. 1991. A variance decomposition for stock returns. Economic Journal, 101: 157–79.  ) are studied with ordinary least squares. Calibration measures and the Brier score and its partition are used for model assessment. The partitions indicate that the ordinary least squares version of Campbell's model does not forecast stock market returns particularly well. While the model offers honest probabilistic forecasts (they are well-calibrated), the model shows little ability to sort events that occur into different groups from events that do not occur. The Yates-partition demonstrates this shortcoming. Calibration metrics do not.     

Efficiency in the NFL betting market: modifying and consolidating research methods

Modifying and consolidating previous research methods to generate more reliable estimates, some fairly weak evidence is found of inefficiency in the NFL betting market resulting from a bias favouring home underdog (against away favourite) teams. In contrast to previous research, no evidence is found that ‘momentum strategies’ generate significant returns in this market.     

Central city crime and suburban economic growth

This paper explores the relationship between inner-city crime patterns and suburban income growth, analysing data on 318 US counties for selected metropolitan statistical areas of 32 states within the United States from 1982 to 1997. The findings suggest that violent crime does seem to have a negative impact on close-in suburbs, with a less negative impact farther away from the central city (becoming positive at some point). While results are not as robust as we had hoped they are consistent with flight to further-out suburbs rather than migration to different metropolitan areas in response to urban crime.     

Forecasting the real output using fractionally integrated techniques

The annual structure of the real GDP in the UK, France, Germany and Italy is examined by means of fractionally integrated techniques. Using a version of a testing procedure due to Robinson (Journal of the American Statistical Association, 84, –37, 1994), it is shown that the series can be specified in terms of I(d?) statistical models with d higher than 1. Thus, the series are nonstationary and non-mean-reverting. The forecasting properties of the selected models for each country are also examined.     

The process followed by PPP data. On the properties of linearity tests

Recent research has reported the lack of correct size in stationarity test for PPP deviations within a linear framework. However, theoretically well motivated non-linear models, such as the ESTAR, appear to parsimoniously fit the PPP data and provide an explanation for the PPP ‘puzzle’. Employing Monte Carlo experiments the size and power of the non-linear tests are analysed against a variety of nonstationary hypotheses. Aslo the ESTAR model is fitted to data from high inflation economies. The results provide further support for ESTAR specification.     

Oligopoly and Merger: A Simple Classroom Game

Professor Miller describes a game which has been used in intermediate price theory courses as well as in introductory classes. Two versions are presented—a duopoly and a six-firm market, both with undifferentiated product and a known market demand schedule. Students are also asked to make a monopoly of the six firms by forming a trust or holding company. Miller contends that the game is more stimulating than lectures aud suspects that it will result in longer retention.