Time Series Tests of Income Convergence with Two Structural Breaks: An Update and Extension

This paper uses newly available long-span data on real per capita incomes from 1900-2001 to test for stochastic convergence in a diverse group of 29 countries. To perform our tests, we utilize the two-break LM unit root test of Lee and Strazicich (2003) and endogenously determine two distinct structural breaks in level and trend for each country. Despite including both OECD and non-OECD countries, we find significant evidence that incomes are stochastically converging. World War II is the most often identified time period of breaks. The results represent slightly more evidence in favor of convergence than reported in the study by Dawson and Sen (forthcoming) using the same sample of countries.

Trend Breaks and Seasonality in the Yugoslav Black Market for Dollars, 1974-1987

We estimate a model of the black market premium for dollars in Yugoslavia from 1974-1987. Unlike previous applications of the model, our analysis addresses nonstationarity in the underlying data by allowing for trend breaks. Endogenous structural break tests indicate the presence of breaks closely associated with the death of Tito and changes in laws affecting the operation of the black market. After accounting for these breaks, we find strong support for the underlying model. In addition, we find evidence consistent with the era of increased government involvement in the black market leading to greater volatility of the premium following regime change.

Nonrenewable Resource Prices: Deterministic or Stochastic Trends?

In this paper we examine temporal properties of eleven natural resource real price series from 1870-1990 by employing a Lagrangian Multiplier unit root test that allows for two endogenously determined structural breaks with and without a quadratic trend. Contrary to previous research, we find evidence against the unit root hypothesis for all price series. Our findings support characterizing natural resource prices as stationary around deterministic trends with structural breaks. This result is important in both a positive and normative sense. For example, without an appropriate understanding of the dynamics of a time series, empirical verification of theories, forecasting, and proper inference are potentially fruitless. More generally, we show that both pre-testing for unit roots with breaks and allowing for breaks in the forecast model can improve forecast accuracy.

Was There a Structural Break in Barry Bonds’ Bat?

We utilize time series tests to investigate if Barry Bonds’ batting has a deterministic or stochastic trend and to test if structural breaks occur. Bonds’ monthly on base percentage plus slugging percentage (OPS) is examined from 1986 to 2007. We find that Bonds’ OPS is stationary around two level and trend breaks. We find that Bonds’ OPS initially follows a positive trend to the age of 28.9 (June 1993), which coincides roughly with the expected peak performance age (27.6) for a MLB batter as identified by Fair (2008). Following this break, we find that Bonds’ OPS was on a plateau until a second break in September 2000. At this point, at the age of 36.1, Bonds’ OPS jumps up unexpectedly and declines slowly thereafter until his retirement in September 2007 at age 43. Key Words: age-effects, peak performance, baseball, OPS, structural break

Minimum Lagrange multiplier unit root test with two structural breaks

The endogenous two-break unit root test of Lumsdaine and Papell is derived assuming no structural breaks under the null. Thus, rejection of the null does not necessarily imply rejection of a unit root per se, but may imply rejection of a unit root without break. Similarly, the alternative does not necessarily imply trend stationarity with breaks, but may indicate a unit root with breaks. In this paper, we propose an endogenous two-break Lagrange multiplier unit root test that allows for breaks under both the null and alternative hypotheses. As a result, rejection of the null unambiguously implies trend stationarity

International evidence of tax smoothing in a panel of industrial countries

A panel of industrial countries is examined for evidence of `tax smoothing’. Tax smoothing results when governments minimize tax distortions over time. The model provides a positive theory of government debt and is due primarily to Barro. Unit root tests are performed in panel data to test the null hypothesis of nonstationary tax rates. Panel regressions are then undertaken to test the null hypothesis that tax rate changes are unpredictable and test for evidence of an alternative hypothesis. Political and economic variables are examined for their ability to predict tax rate changes. Overall, the results cannot reject the null hypotheses and support tax smoothing by national governments

Non-renewable resource prices: Deterministic or stochastic trends?

In this paper, we examine temporal properties of 11 natural resource real price series from 1870 to 1990. Recent studies by Ahrens and Sharma [Trends in natural resource commodity prices: deterministic or stochastic? J. Environ. Econom. Manage. 33(1997)59–74], Berck and Roberts [Natural resource prices: will they ever turn up? J. Environ. Econom. Manage. 31(1996)65–78], and Slade [Grade selection under uncertainty: least cost last and other anomalies, J. Environ. Econom. Manage. 15(1988)189–205], among others, find that many non-renewable resource prices have a stochastic trend. We revisit this issue by employing a Lagrangian multiplier unit root test that allows for two endogenously determined structural breaks with and without a quadratic trend. Contrary to previous research, we find evidence against the unit root hypothesis for all price series. Our findings support characterizing natural resource prices as stationary around deterministic trends with structural breaks. We additionally show that both pre-testing for unit roots with breaks and allowing for breaks in the forecast model can improve forecast accuracy. Overall, the results in this paper are important in both a positive and normative sense; without an appropriate understanding of the dynamics of a time series, empirical verification of theories, forecasting, and proper inference are potentially fruitless

IV threshold cointegration tests and the Taylor rule

ABSTRACT The usual cointegration tests often entail nuisance parameters that hinder precise inference. This problem is even more pronounced in a nonlinear threshold framework when stationary covariates are included. In this paper, we propose new threshold cointegration tests based on instrumental variables estimation. The newly suggested IV threshold cointegration tests have standard distributions that do not depend on any stationary covariates. These desirable properties allow us to formally test for threshold cointegration in a nonlinear Taylor rule. We perform this analysis using real-time U.S. data for several sample periods from 1970 to 2005. In contrast to the linear model, we find strong evidence of cointegration in a nonlinear Taylor rule with threshold effects. Overall, we find that the Federal Reserve is far more policy active when inflation is high than when inflation is low. In addition, we reaffirm the notion that the response to counteract high inflation was weakest in the 1970s and strongest in the Greenspan era

Does Tax Smoothing Differ by the Level of Government? Time Series Evidence from Canada and the United States

The tax smoothing theory is examined for Canada and the United States. A distinction is made between federal and local levels of government. Mobility of taxable resources at the state and local levels may constrain the ability of these governments to smooth tax rates. Testing is undertaken in the frequency domain to see if the cumulated periodogram of the first differenced tax rate series differs from white noise. Testing is undertaken with and without correction for time averaging. Results generally support tax smoothing by both federal governments and the Canadian provinces. Tax smoothing is rejected for state and local governments