Bayesian VARs: Specification Choices and Forecast Accuracy

In this paper we discuss how the point and density forecasting performance of Bayesian vector autoregressions (BVARs) is affected by a number of specification choices. We adopt as a benchmark a common specification in the literature, a BVAR with variables entering in levels and a prior modeled along the lines of Sims and Zha (International Economic Review 1998; 39 : 949–968). We then consider optimal choice of the tightness, of the lag length and of both; evaluate the relative merits of modeling in levels or growth rates; compare alternative approaches to h‐step‐ahead forecasting (direct, iterated and pseudo‐iterated); discuss the treatment of the error variance and of cross‐variable shrinkage; and assess rolling versus recursive estimation. Finally, we analyze the robustness of the results to the VAR size and composition (using also data for France, Canada and the UK, while the main analysis is for the USA). We obtain a large set of empirical results, but the overall message is that we find very small losses (and sometimes even gains) from the adoption of specification choices that make BVAR modeling quick and easy, in particular for point forecasting. This finding could therefore further enhance the diffusion of the BVAR as an econometric tool for a vast range of applications. Copyright © 2013 John Wiley & Sons, Ltd.     

Econometric Methods for Modelling Systems With a Mixture of i(1) and i(0) Variables

This paper considers structural models with both I(1) and I(0) variables. The structural shocks associated with either set of variables could be permanent or transitory. We classify the shocks as (P1,P0) and (T1,T0), where P/T distinguishes permanent/transitory, while 1/0 means they are attached to structural equations with either I(1) or I(0) variables as their ‘dependent’ variable. We show that P0 shocks can affect cointegration analysis and provide a formula to compute the permanent component if they are present. Finally, we reformulate a well‐known empirical structural vector autoregression showing the impact of P0 shocks when there are just long‐run parametric and sign restrictions. Copyright © 2015 John Wiley & Sons, Ltd.     

Exogenous uncertainty and the identification of structural vector autoregressions with external instruments

We provide necessary and sufficient conditions for the identification (point‐identification) of structural vector autoregressions (SVARs) with external instruments considering the case in which r instruments are used to identify g structural shocks of interest, r ≥ g ≥ 1. Novel frequentist estimation methods are discussed by considering both a “partial shocks” identification strategy, where only g structural shocks are of interest and are instrumented, and a “full shocks” identification strategy, where despite g structural shocks being instrumented, all n=g+(n?g) structural shocks of the system can be identified under certain conditions. The suggested approach is applied to investigate empirically whether financial and macroeconomic uncertainty can be approximated as exogenous drivers of US real economic activity, or rather as endogenous responses to first moment shocks, or both. We analyze whether the dynamic causal effects of nonuncertainty shocks on macroeconomic and financial uncertainty are significant in the period after the global financial crisis.     

RARE SHOCKS,GREAT RECESSIONS

We estimate a DSGE (dynamic stochastic general equilibrium) model where rare large shocks can occur, by replacing the commonly used Gaussian assumption with a Student's t‐distribution. Results from the Smets and Wouters (American Economic Review 2007; 97 : 586–606) model estimated on the usual set of macroeconomic time series over the 1964–2011 period indicate that (i) the Student's t specification is strongly favored by the data even when we allow for low‐frequency variation in the volatility of the shocks, and (ii)) the estimated degrees of freedom are quite low for several shocks that drive US business cycles, implying an important role for rare large shocks. This result holds even if we exclude the Great Recession period from the sample. We also show that inference about low‐frequency changes in volatility—and, in particular, inference about the magnitude of Great Moderation—is different once we allow for fat tails. Copyright © 2014 John Wiley & Sons, Ltd.     

Non‐Fundamentalness in Structural Econometric Models: A Review

Current economic theory typically assumes that all the macroeconomic variables belonging to a given economy are driven by a small number of structural shocks. As recently argued, apart from negligible cases, the structural shocks can be recovered if the information set contains current and past values of a large, potentially infinite, set of macroeconomic variables. However, the usual practice of estimating small size causal Vector AutoRegressions can be extremely misleading as in many cases such models could fully recover the structural shocks only if future values of the few variables considered were observable. In other words, the structural shocks may be non‐fundamental with respect to the small dimensional vector used in current macroeconomic practice. By reviewing a recent strand of econometric literature, we show that, as a solution, econometricians should enlarge the space of observations, and thus consider models able to handle very large panels of related time series. Among several alternatives, we review dynamic factor models together with their economic interpretation, and we show how non‐fundamentalness is non‐generic in this framework. Finally, using a factor model, we provide new empirical evidence on the effect of technology shocks on labour productivity and hours worked.     

Accounting for the Political Uncertainty Factor

We build our analysis upon previous work by Bloom et al. (Measuring the Effect of Political Uncertainty. Working Paper, Stanford University, 2012) and Baker et al. (Political Uncertainty: A New Indicator. CentrePiece 2012; 16 (3): 21–23), who estimate the dynamic effects of a shock to a newly constructed surrogate measure of political uncertainty (PU) on the US economy. Comparable to their results we demonstrate that a shock to PU has pervasive effects on the dynamic evolution of the US economy. Using an estimated structural dynamic factor model we find that more globally integrated markets exhibit significantly more pronounced responses than other measures of real economic activity. Impulse responses reveal a small but statistically significant ‘flight‐to‐safety’ effect, depressing government bond yields across the entire term structure following a shock to PU. Forecast error variance decompositions are predominantly composed of supply, demand, and PU shocks over all horizons, with PU shocks contributing less and supply shocks contributing more to forecast errors at longer horizons. Technology shocks, by contrast, are found to affect forecast accuracy closer to impact with quickly decaying contributions over extended forecast horizons. Copyright © 2015 John Wiley & Sons, Ltd.     

The effects of technology shocks on hours and output: a robustness analysis

We analyze the effects of neutral and investment‐specific technology shocks on hours and output. Long cycles in hours are removed in a variety of ways. Hours robustly fall in response to neutral shocks and robustly increase in response to investment‐specific shocks. The percentage of the variance of hours (output) explained by neutral shocks is small (large); the opposite is true for investment‐specific shocks. ‘News shocks’ are uncorrelated with the estimated technology shocks. Copyright © 2009 John Wiley & Sons, Ltd.     

Long‐run neutrality of demand shocks: Revisiting Blanchard and Quah (1989) with independent structural shocks

With reference to a stylized theoretical macromodel, Blanchard and Quah (American Economic Review, 1989, 79, 655–673) identify empirical aggregate supply (e.g., productivity) and demand shocks by assuming that the latter are neutral for economic activity in the long run. Taking advantage of recent contributions to the structural VAR literature and data‐based identification, we find that effects of unique independent non‐Gaussian structural shocks support this assumption. Moreover, unlike the results in Blanchard and Quah, statistically identified supply shocks exhibit (insignificantly) opposite impacts on gross domestic product and unemployment in the short run. In comparison with benchmark results obtained under assumed long‐run neutrality, statistical identification points to a stronger role of aggregate supply shocks for shaping temporary profiles of US unemployment during the recessionary period 1973:Q3–1975:Q1.     

The mean residual of record values at the level of previous records

In the study of reliability of the technical systems, records model plays an important role. Suppose that a technical system is subject to shocks, e.g. peaks of voltages or stresses. The successive large shocks may be viewed as realizations of records from a sequence of identically independent voltages. Assume that the lower limit value of the mth record voltage (stress) is v > 0. Under these conditions, we propose a mean residual of records (MRR’s) for the future records. We study several properties of MRR. We show that the proposed MRR uniquely characterizes the distribution function that generated the sequence of records. It is proved that when the model under study has an increasing hazard rate the corresponding MRR is decreasing. We also compare between two record systems based on their MRR’s when these systems are ordered in terms of their hazard rates.     

Testing for Flexible Nonlinear Trends with an Integrated or Stationary Noise Component

This paper proposes a new test for the presence of a nonlinear deterministic trend approximated by a Fourier expansion in a univariate time series for which there is no prior knowledge as to whether the noise component is stationary or contains an autoregressive unit root. Our approach builds on the work of Perron and Yabu ( 2009a ) and is based on a Feasible Generalized Least Squares procedure that uses a super‐efficient estimator of the sum of the autoregressive coefficients α when α = 1. The resulting Wald test statistic asymptotically follows a chi‐square distribution in both the I(0) and I(1) cases. To improve the finite sample properties of the test, we use a bias‐corrected version of the OLS estimator of α proposed by Roy and Fuller ( 2001 ). We show that our procedure is substantially more powerful than currently available alternatives. We illustrate the usefulness of our method via an application to modelling the trend of global and hemispheric temperatures.     

Keynesian impulses versus Solow residuals: identifying sources of business cycle fluctuations

We employ a neoclassical business‐cycle model to study two sources of business‐cycle fluctuations: marginal efficiency of investment shocks, and total factor productivity shocks. The parameters of the model are estimated using a Bayesian procedure that accommodates prior uncertainty about their magnitudes; from these estimates, posterior distributions of the two shocks are obtained. The postwar US experience suggests that both shocks are important in understanding fluctuations, but that total factor productivity shocks are primarily responsible for beginning and ending recessions. Copyright © 2000 John Wiley & Sons, Ltd.     

Inflation Sensitivity To Monetary Policy: What Has Changed since the Early 1980s?

Have conventional monetary policy instruments maintained the same ability to accommodate undesirable effects of shocks throughout the postwar period? Or has the changed economic environment characterizing the last 30 years diminished the sensitivity of macroeconomic volatility to systematic changes in the conduct of monetary policy? The answer is no to the first question and, consequently, yes to the second question. We estimate a medium‐scale New‐Keynesian model in two subsamples, 1955–79 and 1984–2012, and find that the sensitivity of inflation variance to changes in conventional monetary policy has declined. We document that the changed properties of the labour market largely contributed to this decline.     

Working below and above the line: the research–practice gap in diversity management

In HRM, a line can be drawn that distinguishes research on formal organisational programmes (above‐the‐line research) from research on organisational practices as they are experienced by employees (below‐the‐line research). Diversity management research has heavily emphasised below‐the‐line research using methodologies that measure employee perceptions of diversity management activities. This research demonstrates an impact of diversity management on employee reactions and identifies unit‐level factors (e.g. leader behaviour) that impact the effectiveness of diversity management activities. However, below‐the‐line research is not able to answer HR professionals' questions about which diversity management activities should be adopted when, and so a research–practice gap is developing. I explain how both academics and practitioners would benefit from more above‐the‐line research examining the impact of formal organisational diversity management activities as reported by senior managers or documented in organisational records.     

Combining Time Variation and Mixed Frequencies: an Analysis of Government Spending Multipliers in Italy

In this paper, we propose a time‐varying parameter vector autoregression (VAR) model with stochastic volatility which allows for estimation on data sampled at different frequencies. Our contribution is twofold. First, we extend the methodology developed by Cogley and Sargent (Drifts and volatilities: monetary policies and outcomes in the post WWII U.S. Review of Economic Studies 2005; 8 : 262–302) and Primiceri (Time varying structural vector autoregressions and monetary policy. Review of Economic Studies 2005; 72 : 821–852) to a mixed‐frequency setting. In particular, our approach allows for the inclusion of two different categories of variables (high‐frequency and low‐frequency) into the same time‐varying model. Second, we use this model to study the macroeconomic effects of government spending shocks in Italy over the 1988:Q4–2013:Q3 period. Italy—as well as most other euro area economies—is characterized by short quarterly time series for fiscal variables, whereas annual data are generally available for a longer sample before 1999. Our results show that the proposed time‐varying mixed‐frequency model improves on the performance of a simple linear interpolation model in generating the true path of the missing observations. Second, our empirical analysis suggests that government spending shocks tend to have positive effects on output in Italy. The fiscal multiplier, which is maximized at the 1‐year horizon, follows a U‐shape over the sample considered: it peaks at around 1.5 at the beginning of the sample; it then stabilizes between 0.8 and 0.9 from the mid 1990s to the late 2000s, before rising again to above unity during the recent crisis. Copyright © 2015 John Wiley & Sons, Ltd.     

General‐to‐Specific Model Selection Procedures for Structural Vector Autoregressions*

Structural vector autoregressive (SVAR) models have emerged as a dominant research strategy in empirical macroeconomics, but suffer from the large number of parameters employed and the resulting estimation uncertainty associated with their impulse responses. In this paper, we propose general‐to‐specific (Gets) model selection procedures to overcome these limitations. It is shown that single‐equation procedures are generally efficient for the reduction of recursive SVAR models. The small‐sample properties of the proposed reduction procedure (as implemented using PcGets) are evaluated in a realistic Monte Carlo experiment. The impulse responses generated by the selected SVAR are found to be more precise and accurate than those of the unrestricted VAR. The proposed reduction strategy is then applied to the US monetary system considered by Christiano, Eichenbaum and Evans (Review of Economics and Statistics, Vol. 78, pp. 16–34, 1996) . The results are consistent with the Monte Carlo and question the validity of the impulse responses generated by the full system.     

A study on the mean past lifetime of the components of (n − k + 1)-out-of-n system at the system level

In the present paper, we consider a (n − k + 1)-out-of-n system with identical components where it is assumed that the lifetimes of the components are independent and have a common distribution function F. We assume that the system fails at time t or sometime before t, t > 0. Under these conditions, we are interested in the study of the mean time elapsed since the failure of the components. We call this as the mean past lifetime (MPL) of the components at the system level. Several properties of the MPL are studied. It is proved that the relation between the proposed MPL and the underlying distribution is one-to-one. We have shown that when the components of the system have decreasing reversed hazard then the MPL of the system is increasing with respect to time. Some examples are also provided.     

Elastic attention,risk sharing,and international comovements

In this paper we examine the effects of elastic information-processing capacity (or elastic attention) proposed in Sims (2010) on international consumption and income correlations in a tractable small open economy (SOE) model with exogenous income processes. We find that in the presence of capital mobility in financial markets, elastic attention due to a fixed information-processing cost lowers the international consumption correlations by generating heterogeneous consumption adjustments to income shocks across countries facing different macroeconomic uncertainty. In addition, we show that elastic attention can improve the model’s predictions for the other key moments of the joint dynamics of consumption and income.     

Embeddedness across contexts: A two‐country study on the additive and buffering effects of job embeddedness on employee turnover

Despite the growing body of literature on the effects of job embeddedness on turnover, there are few studies on how job embeddedness operates in different countries. This study, based on the Conservation of Resources theory, addresses this research gap by investigating both the additive and the buffering effects of on‐the‐job and off‐the‐job embeddedness using employee data from China (n = 373) and Switzerland (n = 268). Results showed that on‐the‐job embeddedness reduced the likelihood of turnover more strongly in Switzerland than in China (additive effect). Additionally, in China, the unsolicited job offer–turnover relationship was stronger when employees had lower levels of off‐the‐job embeddedness (buffering effect). This research contributes to the understanding of the relative role of on‐the‐job and off‐the‐job embeddedness for turnover in different countries.     

Intergenerational Transmission of Fertility Patterns*

Recent studies by economists have focused on cultural transmission from the origin country rather than the origin family. Our paper extends this research by investigating how family‐specific‘cultural transmission’ can affect fertility rates. Following Machado and Santos Silva [Journal of the American Statistical Association (2005) Vol. 100, p. 1226] and Miranda [Journal of Population Economics (2008) Vol. 21, p. 67], we estimate count data quantile regression models using the British Household Panel Survey. We find that a woman's origin‐family size is positively associated with completed fertility in her destination family. A woman's country of birth also matters for her fertility. For a sub‐sample of continuously partnered men and women, both partners’ origin‐family sizes significantly affect destination‐family fertility.     

Truth and Robustness in Cross‐country Growth Regressions*

We re‐examine studies of cross‐country growth regressions by Levine and Renelt (American Economic Review, Vol. 82, 1992, pp. 942–963) and Sala‐i‐Martin (American Economic Review, Vol. 87, 1997a, pp. 178–183; Economics Department, Columbia, University, 1997b). In a realistic Monte Carlo experiment, their variants of Edward Leamer's extreme‐bounds analysis are compared with a cross‐sectional version of the general‐to‐specific search methodology associated with the LSE approach to econometrics. Levine and Renelt's method has low size and low power, while Sala‐i‐Martin's method has high size and high power. The general‐to‐specific methodology is shown to have a near nominal size and high power. Sala‐i‐Martin's method and the general‐to‐specific method are then applied to the actual data from Sala‐i‐Martin's original study.