Small‐sample testing inference in symmetric and log‐symmetric linear regression models

This paper deals with the issue of testing hypotheses in symmetric and log‐symmetric linear regression models in small and moderate‐sized samples. We focus on four tests, namely, the Wald, likelihood ratio, score, and gradient tests. These tests rely on asymptotic results and are unreliable when the sample size is not large enough to guarantee a good agreement between the exact distribution of the test statistic and the corresponding chi‐squared asymptotic distribution. Bartlett and Bartlett‐type corrections typically attenuate the size distortion of the tests. These corrections are available in the literature for the likelihood ratio and score tests in symmetric linear regression models. Here, we derive a Bartlett‐type correction for the gradient test. We show that the corrections are also valid for the log‐symmetric linear regression models. We numerically compare the various tests and bootstrapped tests, through simulations. Our results suggest that the corrected and bootstrapped tests exhibit type I probability error closer to the chosen nominal level with virtually no power loss. The analytically corrected tests as well as the bootstrapped tests, including the Bartlett‐corrected gradient test derived in this paper, perform with the advantage of not requiring computationally intensive calculations. We present a real data application to illustrate the usefulness of the modified tests.     

The estimation of utility‐consistent labor supply models by means of simulated scores

We consider a utility‐consistent static labor supply model with flexible preferences and a nonlinear and possibly non‐convex budget set. Stochastic error terms are introduced to represent optimization and reporting errors, stochastic preferences, and heterogeneity in wages. Coherency conditions on the parameters and the support of error distributions are imposed for all observations. The complexity of the model makes it impossible to write down the probability of participation. Hence we use simulation techniques in the estimation. We compare our approach with various simpler alternatives proposed in the literature. Both in Monte Carlo experiments and for real data the various estimation methods yield very different results. Copyright © 2008 John Wiley & Sons, Ltd.     

Accounting for labor demand effects in structural labor supply models

When assessing the effects of policy reforms on the labor market, most studies only focus on labor supply. The interaction of supply and demand is not explicitly modeled, which might lead to biased estimates of potential labor market outcomes. This paper proposes a straightforward method to remedy this shortcoming. We use information on firms' labor demand behavior and feed them into a structural labor supply model, completing the partial analysis of the labor market on the microdata level. We show the performance and relevance of our extension by introducing a pure labor supply side reform, the workfare concept, in Germany and simulating the labor market outcome of the reform. We find that demand effects offset about 25% of the positive labor supply effect of the policy reform.     

Small‐sample confidence intervals for multivariate impulse response functions at long horizons

Existing methods for constructing confidence bands for multivariate impulse response functions may have poor coverage at long lead times when variables are highly persistent. The goal of this paper is to propose a simple method that is not pointwise and that is robust to the presence of highly persistent processes. We use approximations based on local‐to‐unity asymptotic theory, and allow the horizon to be a fixed fraction of the sample size. We show that our method has better coverage properties at long horizons than existing methods, and may provide different economic conclusions in empirical applications. We also propose a modification of this method which has good coverage properties at both short and long horizons. Copyright © 2006 John Wiley & Sons, Ltd.     

Cross‐sectional Dependency and Size Distortion in a Small‐sample Homogeneous Panel Data Unit Root Test*

In this paper, we investigate the effects of cross‐sectional disturbance correlation in a homogeneous panel data unit root test. As reported by other authors, the unit root test has incorrect size in the presence of cross‐sectional correlation. We suggest that a previously known estimator can be used to reduce the size distortions. We supply response surface estimates for critical values and study the size characteristics of the proposed test. We find that the suggested estimator performs well in small‐sample homogeneous panel data unit root tests. The reduction in size distortion comes at a small cost of lower power against a stationary alternative.     

Simple tests for sample selection bias in censored and discrete choice models

This paper presents two simple tests of sample selection bias for models where the primary equation of interest has a censored or discrete dependent variable. The first test is derived as a conditional moment test and can be implemented in a regression-based framework. The second test is an extension of the testing procedures proposed by Heckman (1979) and Vella (1993) and is a t-test on a constructed variable in an auxiliary equation. The utility of the tests is illustrated in a model determining the receipt of work conditioned nonwage labour income over a subsample of working women.     

Simulation estimation of two‐tiered dynamic panel Tobit models with an application to the labor supply of married women

In this paper a computationally practical simulation estimator is proposed for the two‐tiered dynamic panel Tobit model originally developed by Cragg ( 1971 ). The log‐likelihood function simulated through procedures based on a recursive algorithm formulated by the Geweke–Hajivassiliou–Keane simulator is maximized. The simulation estimators are then applied to study the labor supply of married women. The rich dynamic structure of the labor force participation decision as well as hours worked decisions that are conditional on the participation of married women are identified by using the proposed simulation estimators. The average partial effects of the participation and hours worked decisions for married women in response to fertility decisions and increases in the husband's income are also investigated. It is found that the hypothesis that the fertility decision is exogenous and the hypothesis that the husband's income is exogenous to married women's labor supply function are both rejected in the dynamic and static two‐tiered models. Moreover, children aged between 6 and 13 years old may have a negative impact on the hours worked decision for married women that is conditional on their participation. However, these children may provide some positive incentives for married women to participate in the labor force. Copyright © 2009 John Wiley & Sons, Ltd.     

Strategic Staffing and Small‐Firm Performance

Although staffing can be a critical determinant of whether small businesses succeed or fail, there has been less research in this area than might be expected, given the large numbers of such firms. While there has been some research on specific recruiting and selection practices, there has been little attention to the strategic aspects of staffing. We investigated relationships between strategic approaches to staffing and small‐firm performance using lagged survey data from 139 founders and owners of small firms. Results indicate that recruiting approaches imitating the practices (processes) of larger businesses are positively related to a perceptual measure of firm performance. Selection approaches stressing a growth orientation are also positively related to firm performance. Finally, founders’ and owners’ perceptions of the strategic importance of human resources moderate the relationship of firm performance with imitative recruiting practices as well as with growth‐oriented selection practices. An important contribution of this article is that contextual knowledge facilitates our understanding of the performance implications of staffing practices in small firms. © 2015 Wiley Periodicals, Inc.     

Binary response panel data models with sample selection and self‐selection

We consider estimating binary response models on an unbalanced panel, where the outcome of the dependent variable may be missing due to nonrandom selection, or there is self‐selection into a treatment. In the present paper, we first consider estimation of sample selection models and treatment effects using a fully parametric approach, where the error distribution is assumed to be normal in both primary and selection equations. Arbitrary time dependence in errors is permitted. Estimation of both coefficients and partial effects, as well as tests for selection bias, are discussed. Furthermore, we consider a semiparametric estimator of binary response panel data models with sample selection that is robust to a variety of error distributions. The estimator employs a control function approach to account for endogenous selection and permits consistent estimation of scaled coefficients and relative effects.     

Finite‐sample comparison of alternative methods for estimating dynamic panel data models

The Wooldridge method is based on a simple and novel strategy to deal with the initial values problem in nonlinear dynamic random‐effects panel data models. The characteristic of the method makes it very attractive in empirical applications. However, its finite sample performance and robustness are not fully known as of yet. In this paper we investigate the performance and robustness of this method in comparison with an ideal case in which the initial values are known constants; the worst scenario is based on an exogenous initial values assumption, and the Heckman's reduced‐form approximation method, which is widely used in the literature. The dynamic random‐effects probit and Tobit (type I) models are used as working examples. Various designs of the Monte Carlo experiments and two further empirical illustrations are provided. The results suggest that the Wooldridge method works very well only for the panels of moderately long duration (longer than 5–8 periods). Heckman's reduced‐form approximation is suggested for short panels (shorter than 5 periods). It is also found that all the methods tend to perform equally well for panels of long duration (longer than 15–20 periods). Copyright © 2011 John Wiley & Sons, Ltd.     

Testing Stationarity in Small‐ and Medium‐Sized Samples when Disturbances are Serially Correlated*

In this article, we study the size distortions of the KPSS test for stationarity when serial correlation is present and samples are small‐ and medium‐sized. It is argued that two distinct sources of the size distortions can be identified. The first source is the finite‐sample distribution of the long‐run variance estimator used in the KPSS test, while the second source of the size distortions is the serial correlation not captured by the long‐run variance estimator because of a too narrow choice of truncation lag parameter. When the relative importance of the two sources is studied, it is found that the size of the KPSS test can be reasonably well controlled if the finite‐sample distribution of the KPSS test statistic, conditional on the time‐series dimension and the truncation lag parameter, is used. Hence, finite‐sample critical values, which can be applied to reduce the size distortions of the KPSS test, are supplied. When the power of the test is studied, it is found that the price paid for the increased size control is a lower raw power against a non‐stationary alternative hypothesis.     

Some labor market effects of labor supply responses to transfer programs

This paper utilizes a large-scale micro-simulation computer model to examine whether adverse effects on work effort initially resulting from implementation of a new income transfer plan might be partially offset through “second-round” responses by employers and by unemployed transfer recipients. The findings suggest that employer responses to shifts in labor supply curves that follow introduction of a transfer program have little potential for offsetting reductions in hours worked. Under certain circumstances, however, responses by the unemployed do offer a potential offset, particularly if in the absence of the program there would have been considerable excess supply of labor within the economy.     

Local Powers of Optimal One‐sample and Multi‐sample Tests for the Concentration of Fisher‐von Mises‐Langevin Distributions

One‐sample and multi‐sample tests on the concentration parameter of Fisher‐von Mises‐Langevin distributions on (hyper‐)spheres have been well studied in the literature. However, only little is known about their behaviour under local alternatives, which is due to complications inherent to the curved nature of the parameter space. The aim of the present paper therefore consists in filling that gap by having recourse to the Le Cam methodology, which has recently been adapted from the linear to the spherical setup. We obtain explicit expressions of the powers for the most efficient one‐ and multi‐sample tests. As a nice by‐product, we are also able to write down the powers (against local Fisher‐von Mises‐Langevin alternatives) of the celebrated Rayleigh test of uniformity. A Monte Carlo simulation study confirms our theoretical findings and shows the empirical powers of the above‐mentioned procedures.     

Cross‐border Small‐scale Trading in South‐Eastern Europe: Do Embeddedness and Social Capital Explain Enough?

The article analyses cross‐border small‐scale trading (CBST) from the perspective of New Institutional Economics. It offers an alternative analytical starting point to this topic, which is mainly tackled by sociologists and anthropologists. It is argued that concepts like social capital or social embeddedness can be of certain analytical use but that they hardly suffice to explain human behaviour in a detailed manner. The case of reference is the institution of bribery as it evolved in the first half of the 1990s at the Bulgarian‐Turkish border.     

Multivariate residual‐based finite‐sample tests for serial dependence and ARCH effects with applications to asset pricing models

In this paper, we propose several finite‐sample specification tests for multivariate linear regressions (MLR). We focus on tests for serial dependence and ARCH effects with possibly non‐Gaussian errors. The tests are based on properly standardized multivariate residuals to ensure invariance to error covariances. The procedures proposed provide: (i) exact variants of standard multivariate portmanteau tests for serial correlation as well as ARCH effects, and (ii) exact versions of the diagnostics presented by Shanken ( 1990 ) which are based on combining univariate specification tests. Specifically, we combine tests across equations using a Monte Carlo (MC) test method so that Bonferroni‐type bounds can be avoided. The procedures considered are evaluated in a simulation experiment: the latter shows that standard asymptotic procedures suffer from serious size problems, while the MC tests suggested display excellent size and power properties, even when the sample size is small relative to the number of equations, with normal or Student‐t errors. The tests proposed are applied to the Fama–French three‐factor model. Our findings suggest that the i.i.d. error assumption provides an acceptable working framework once we allow for non‐Gaussian errors within 5‐year sub‐periods, whereas temporal instabilities clearly plague the full‐sample dataset. Copyright © 2009 John Wiley & Sons, Ltd.     

A Multi-state model of state dependence in labor supply: Intertemporal labor supply effects of a shift from joint to individual taxation

In this paper I develop an intertemporal discrete choice model of female labor supply to analyze the effects of true state dependence and its effect on labor supply behavior over time. The estimation results show that state dependence is significantly positive at the extensive margin and lower but in general still significant at the intensive margin. I apply this model to study the short and long run labor supply effects of a fundamental reform of the German income tax system, i.e. the shift from joint to individual taxation of married couples and show that labor supply responses are significantly higher in the long run than in the short run.     

Off-farm labor supply and labor markets in rapidly changing circumstances: Bulgaria during transition

This study examines off-farm labor supply in the rapidly changing conditions of Bulgaria during the 1990s. In doing so, we make use of three different waves of the Bulgarian Integrated Household Survey, each reflecting remarkably different environmental conditions. The results suggest that standard theories of off-farm labor supply provide little guidance in situations characterized by chronic excess supply in the off-farm labor market and/or rapidly changing circumstances. In particular, the results show (1) that off-farm employment throughout the transition was predominantly determined by demand rather than by supply, and (2) that the magnitude and statistical significance of the various determinants are very sensitive to changing environmental conditions. As such, the results can be extremely relevant for both theory and policy for the many countries which may still need to go through privatization and painful restructuring as a result of financial crises and globalization.     

Differentiated‐product distribution in a dual‐channel supply chain

This study presents a theoretical framework to explore the mechanism of firms' preference for different distribution strategies. The results indicate that the manufacturer, retailer, and e‐tailer would prefer the distribution strategy of selling low‐end and high‐end products through offline and online channels, respectively, when consumers are minimally sensitive to the product‐quality differentiation. By contrast, supply‐chain firms would prefer the distribution strategy of selling high‐end and low‐end products through offline and online channels when consumers are significantly sensitive to the product‐quality differentiation. Firms demonstrate different preferences for distribution strategy when consumers are moderately sensitive to product‐quality differentiation.     

The effect of non-pecuniary motivations on labor supply

People value work not only as a means of earning income to satisfy their consumption needs but also as a direct source of satisfaction for its socio-psychological effects (non-pecuniary benefits). I show that once non-pecuniary effects of working time are incorporated in the standard labor-supply model: (i) the wage rate under-estimates (over-estimates) the true opportunity cost of non-work/leisure time when working time has non-pecuniary benefits (costs), (ii) non-pecuniary work motivations can substitute for monetary wages as work incentives, (iii) at very low wage rates, work can become a net source of utility, and (iv) the implied shape of labor-supply curve differs starkly from those implied by standard theory. I identify conditions under which a greater non-pecuniary work motivation induces a larger supply of labor, and examine the effects of non-wage income on supplies of paid work and voluntary work when there are non-pecuniary benefits associated with both types of work.     

Environmental Strategy and Competitive Advantage: The Role of Small‐ and Medium‐Sized enterprises' Dynamic Capabilities

Drawing on the resource‐based theory and institutional theory, we develop a framework to explain the processes by which the environmental strategy of small‐ and medium‐sized enterprises (SMEs) contributes to their competitive advantage. We test our assumption using data collected from 214 UK‐based SMEs in the technology sector. We find that the effects of environmental strategy can lead to development of their marketing competence, as well as research and development (R&D) competence, which ultimately contributes to superior financial performance. We also find that a reciprocal causal relationship exists between SMEs' marketing and R&D competences. Combined, we reveal the presence of a serial multiple mediation relationship between SMEs' environmental strategy and financial performance through marketing competence and then R&D competence, or vice versa. Our study offers important academic and managerial implications, and also points out future research directions. Copyright © 2016 John Wiley & Sons, Ltd and ERP Environment