Does the labor-income process contain a unit root? Evidence from individual-specific time series

Calibrations of models related to life-cycle behavior of consumption and saving often invoke the important assumption of a unit root in individuals׳ labor-income process. We for the first time test this assumption using methods for univariate time series. Based on longitudinal register data from 1968 to 2005, we first estimate an autoregressive model for each individual using a method for approximately median-unbiased estimation. We then exploit the resulting distribution of the individual-specific estimates to draw inference about the presence of a unit root. Results indicate that earnings for the representative worker are governed by a process where shocks to earnings have moderate persistence and are both economically and statistically significantly different from having permanent effects. These results question the heavy use of unit-root processes for earnings.     

Forecast combinations under structural break uncertainty

This paper proposes two new weighting schemes that average forecasts based on different estimation windows in order to account for possible structural change. The first scheme weights the forecasts according to the values of reversed ordered CUSUM (ROC) test statistics, while the second weighting method simply assigns heavier weights to forecasts that use more recent information. Simulation results show that, when structural breaks are present, forecasts based on the first weighting scheme outperform those based on a procedure that simply uses ROC tests to choose and forecast from a single post-break estimation window. Combination forecasts based on our second weighting scheme outperform equally weighted combination forecasts. An empirical application based on a NAIRU Phillips curve model for the G7 countries illustrates these findings, and also shows that combination forecasts can outperform the random walk forecasting model.     

Estimating DSGE models across time and frequency

Using a wavelet-based decomposition, this paper exploits the information in the data usually employed in the estimation of DSGE models. A simple New Keynesian model featuring price and wage rigidities is estimated for the United States across different frequencies. The estimations indicate that most structural parameters exhibit a frequency-dependent behavior. The impulse response functions also indicate frequency-dependent responses of output to the exogenous shocks. For lower frequencies, there are more persistent effects, especially for preference and technology shocks.     

Varying Coefficient Regression Models: A Review and New Developments

Varying coefficient regression models are known to be very useful tools for analysing the relation between a response and a group of covariates. Their structure and interpretability are similar to those for the traditional linear regression model, but they are more flexible because of the infinite dimensionality of the corresponding parameter spaces. The aims of this paper are to give an overview on the existing methodological and theoretical developments for varying coefficient models and to discuss their extensions with some new developments. The new developments enable us to use different amount of smoothing for estimating different component functions in the models. They are for a flexible form of varying coefficient models that requires smoothing across different covariates' spaces and are based on the smooth backfitting technique that is admitted as a powerful technique for fitting structural regression models and is also known to free us from the curse of dimensionality.     

Monetary regime choice in Singapore: Would a Taylor rule outperform exchange-rate management?

A DSGE–VAR approach was adopted to examine the managed exchange-rate system at work in Singapore and to ask if the country had any reason to fear floating the exchange rate and adopting a Taylor rule. The results showed that, in terms of overall inflation volatility, the exchange rate rule had a comparative advantage over the Taylor rule when export-price shocks were the major sources of real volatility while a Taylor rule was preferable when domestic productivity shocks were dominant. The exchange-rate rule also dominated the Taylor rule for reducing inflation persistence.     

Taking financial frictions to the data

We estimate a Dynamic Stochastic General Equilibrium (DSGE) model with various financial frictions and analyze how well the model explains the Great Recession. Predictive analysis shows that the model can only slightly better explain the large deviation from trend during the crisis relative to a model without financial frictions. Specifically, the risk premium shock, which is a shock to the external finance premium of the entrepreneurs׳ leverage, explains the largest part of the investment downfall during the crisis. However, the ‘balance sheet’ channel of financial frictions in the model, which structurally links balance sheet conditions of financial intermediaries and nonfinancial borrowers to their borrowing rates, is estimated to be weak. We examine alternative prior specifications for how the financial frictions enter the model and continue to find a limited role for these frictions. Rolling-window estimation provides evidence for substantial time variation in parameters governing financial frictions. We conclude that the well-known financial frictions studied in this paper are not able to explain the financial crisis in a linearized and estimated model.     

基于Arduino的MiFare射频卡读写机制的研究

本文阐述了在Arduino UNO上对MiFare One卡射频识别卡进行读写的软件实现,并重点描述了阅读器与卡片之间的通信过程。     

Properties of Census Dual System Population Size Estimators

We study parametric and non‐parametric approaches for assessing the accuracy and coverage of a population census based on dual system surveys. The two parametric approaches being considered are post‐stratification and logistic regression, which have been or will be implemented for the US Census dual system surveys. We show that the parametric model‐based approaches are generally biased unless the model is correctly specified. We then study a local post‐stratification approach based on a non‐parametric kernel estimate of the Census enumeration functions. We illustrate that the non‐parametric approach avoids the risk of model mis‐specification and is consistent under relatively weak conditions. The performances of these estimators are evaluated numerically via simulation studies and an empirical analysis based on the 2000 US Census post‐enumeration survey data.     

Long term effects of an intervention in the outdoor environment—a comparison of older people’s perception in two residential areas,in one of which accessibility improvements were introduced

Walking and participating in activities outdoors in old age can be restricted both by the physical capacity of the individual and by the maintenance and/or the design of the outdoor environment. The purpose of this paper is to compare frequency of walking and frequency of activity outside the home, reported environmental barriers and valuation of the outdoor environment between two areas, in one of which there was an intervention in the outdoor environment 5–8 years prior to this study. The paper is based on a questionnaire sent out in 2011, to all residents 65 years and older in two different areas, the Study Area, an area with an intervention, and the Reference Area. The results show that reports on functional limitations, use of mobility devices and walking difficulties were similar in both areas. Despite that, respondents in the Study Area had a significantly higher frequency of walking and they also participated to a higher degree in activities than respondents in the Reference Area, even though they reported more environmental barriers. The valuation of the outdoor environment was, however, similar in both areas. The results indicate that older people benefit from interventions in the outdoor environment. However, the results also emphasize the importance of good maintenance of the environment.     

Bond Pricing with a Time‐Varying Price of Risk in an Estimated Medium‐Scale Bayesian DSGE Model

New Keynesian model in which households have Epstein–Zin preferences with time‐varying risk aversion and the central bank has a time‐varying inflation target can match the dynamics of nominal bond prices in the U.S. economy well. The model generates a large steady‐state term spread and its fitting errors for bond yields are comparable to those obtained from a nonstructural three‐factor model, and one‐third smaller than in models with a constant inflation target or risk aversion. Including data on interest rates has large effects on variance decompositions, making investment technology shocks much less important than found in other recent papers.