Panel Unit Root Tests in the Presence of Cross-Sectional Dependencies: Comparison and Implications for Modelling

Several panel unit root tests that account for cross-section dependence using a common factor structure have been proposed in the literature recently. Pesaran's (2007 Pesaran , M. H. ( 2007 ). A simple panel unit root test in the presence of cross section dependence . Journal of Applied Econometrics 22 : 265 – 312 .[Crossref], [Web of Science ®] , [Google Scholar]) cross-sectionally augmented unit root tests are designed for cases where cross-sectional dependence is due to a single factor. The Moon and Perron (2004 Moon , H. R. , Perron , B. (2004). Testing for a unit root in panels with dynamic factors. Journal of Econometrics 122:81–126.[Crossref], [Web of Science ®] , [Google Scholar]) tests which use defactored data are similar in spirit but can account for multiple common factors. The Bai and Ng (2004a Bai , J. , Ng , S. ( 2004a ). A PANIC attack on unit roots and cointegration . Econometrica 72 : 1127 – 1177 .[Crossref], [Web of Science ®] , [Google Scholar]) tests allow to determine the source of nonstationarity by testing for unit roots in the common factors and the idiosyncratic factors separately. Breitung and Das (2008 Breitung , J. , Das , S. ( 2008 ). Testing for unit roots in panels with a factor structure . Econometric Theory 24 : 88 – 108 .[Crossref], [Web of Science ®] , [Google Scholar]) and Sul (2007 Sul , D. ( 2007 ) . Panel Unit Root Tests Under Cross Section Dependence with Recursive Mean Adjustment . Mimeo : University of Auckland . [Google Scholar]) propose panel unit root tests when cross-section dependence is present possibly due to common factors, but the common factor structure is not fully exploited.

This article makes four contributions: (1) it compares the testing procedures in terms of similarities and differences in the data generation process, tests, null, and alternative hypotheses considered, (2) using Monte Carlo results it compares the small sample properties of the tests in models with up to two common factors, (3) it provides an application which illustrates the use of the tests, and (4) finally, it discusses the use of the tests in modelling in general.     

Natural Exponential Families and Generalized Hypergeometric Measures

Let ν be a positive Borel measure on ?ⁿ and _pF_q(a₁,…, a_p; b₁,…, b_q; s) be a generalized hypergeometric series. We define a generalized hypergeometric measure, μ_p,q := _pF_q(a₁,…, a_p; b₁,…, b_q;ν), as a series of convolution powers of the measure ν, and we investigate classes of probability distributions which are expressible as such a measure. We show that the Kemp (1968 Kemp , A. W. ( 1968 ). A wide class of discrete distributions and the associated differential equations . Sankhyā, Ser. A 30 : 401 – 410 . [Google Scholar]) family of distributions is an example of μ_p,q in which ν is a Dirac measure on ?. For the case in which ν is a Dirac measure on ?ⁿ, we relate μ_p,q to the diagonal natural exponential families classified by Bar-Lev et al. (1994 Bar-Lev , S. K. , Bshouty , D. , Enis , P. , Letac , G. , Lu , I. , Richards , D. ( 1994 ). The diagonal natural exponential families on ? ⁿ and their classification . J. Theoret. Probab. 7 : 883 – 929 .[Crossref] , [Google Scholar]). For p < q, we show that certain measures μ_p,q can be expressed as the convolution of a sequence of independent multi-dimensional Bernoulli trials. For p = q, q + 1, we show that the measures μ_p,q are mixture measures with the Dufresne and Poisson-stopped-sum probability distributions as their mixing measures.     

Bounds on Sample Variation Measures Based on Majorization

Using majorization theory, upper and lower bounds are derived for different measures of variation as progressively more items of information are available about the sample data. As a convenient starting point, bounds are first established for a one-parameter family of variation measures, which is a generalized mean difference measure of which Gini's mean difference, the standard deviation, and the range are particular cases. While, as pointed out, some of the derived bounds are well known, others do not appear to have been published and are tighter than established bounds. Some 40 different bounds are derived, besides any number of bounds given for the generalized family of variation measures. A number of interesting inequalities are also derived on the basis of some of the bounds. While the bounds have been developed in terms of real-valued sample data generally, the paper concludes with a brief discussion of the bounds for categorical data when the sample data consists of frequencies (counts).     

Displacement and household adaptation: insured by the spouse or the state?

We investigate the added worker effect in a setting where female labour supply is high and the welfare state is generous. We trace couples’ labour supply and income development following the husband’s job displacement. We find no support for the added worker effect for the full sample of households. However, the added worker effect seems to be at work for subsamples characterised by households where the spouses are not working in the same industry and where the wife did not work full time pre-displacement. When using a measure of total household income, which includes public transfers, we find that the negative income impact of displacement is reduced by approximately 60 to 70 % when we also adjust for lower tax payments. Results suggest that income loss due to displacement is mitigated more by social welfare payments than by labour supply responses of the spouse.     

Is it racism? Skepticism and resistance towards ethnic minority care workers among older care recipients

The study investigates the occurrence and character of skepticism and resistance towards ethnic minority care workers among older care recipients in a municipality in Sweden. Twelve representatives of caregiver organizations were interviewed about their experience of this phenomenon. Three additional interviews were conducted with ethnic minority care workers. Representatives described the problem as rare and mostly occurring as language difficulties or as a temporary problem characterized as a fear of the unknown among some care recipients. They tended to apply a pragmatic or pathologizing approach when talking about causes of and solutions to the problem. These approaches enabled care providers to comply with "potential racism" without challenging an official ideology of anti-racism. In contrast, staff of foreign descent described the problem as more frequent and severe, particularly for short-term employees who experience many first-time encounters with care recipients.     

Borda and Condorcet: Some Distance Results

This paper provides a distance based analysis of the Borda rule with respect to Condorcet’s criterion. It shows that the minimal Condorcet consistency present in the Borda rule, whenever a Condorcet winner (the alternative that wins against every other alternative in a pairwise contest) exists, disappears in the case of voting cycles. First, it is shown that for certain preference profiles the Borda winner is furthest from being a Condorcet winner. Second, it is shown that there exist preference profiles for which the Borda winner is closest from being a Condorcet loser (the alternative that loses against every other alternative in a pairwise contest).     

The question of community attachment revisited

In this paper we compare the relative effects of satisfaction with specific community (neighborhood) attributes and social integration into the community on community attachment. Previous research on community attachment has not assessed the importance of satisfaction with specific attributes as a determinant of attachment. Instead, this research has focussed on integration into the social life of a community as the primary source of community attachment. We find that although social integration has the more important effect on attachment, satisfaction with specific community attributes also has a statistically significant effect. People who are satisfied with the general physical appearance, the noise level, and the quality of neighbors in their communities tend to be more attached to them than those who are less satisfied. We address the theoretical and policy implications of this finding. In short, this finding implies, contrary to previous thought, that it is possible for there to be higher levels of attachment to communities that appear to be lacking a well‐developed social life. It also implies that levels of attachment to communities could be enhanced by programs that improve certain features of the physical environment which are seen as indicative of the quality of communities as good places to live.     

What Happens to Defined Contribution Accounts When Labor Markets and Financial Markets Move Together?

The relationship among earnings, savings, and retirement is well known; however, the linkage between labor market outcomes and financial market performance is generally unacknowledged. We examine the implications of the link between labor markets and financial markets for workers who save money in individual retirement accounts. Specifically, differences in labor market outcomes across groups may imply differences in the timing of investments, which may reduce savings over time for these groups compared to their counterparts. Using monthly data from the Current Population Survey (1979–2002), we generate hypothetical investment portfolios using stock and bond indices. We exploit differences across demographic groups in unemployment and wage growth and use these differences to examine each group's investment outcomes. We then disaggregate the total effects into short-term and long-term components. We find some evidence of short-term market timing effects on investment, but we find much larger long-term effects for some groups. Our findings suggest that, for many people, the retirement savings losses associated with the timing of markets are similar to the costs of annuitizing savings upon retirement. The differences are especially pronounced by education and gender.     

International social indicators: The OECD experience

One of the few efforts to develop an operational set of international social indicators is underway through the Organization for Economic Cooperation and Development. The paper describes the OECD plan and gives some preliminary appraisal of the completed first phase of the work, the definition of the elements of well-being for which specific indicators of change should be developed. Attention is directed to certain aspects of the overall strategy being pursued by OECD including its careful delimitation of scope to the one type of social indicators (herein termed well-being indicators) for which international agreement now appears possible although very difficult. A possible governmental strategy for development of more comprehensive social indicators in the longer term context is suggested.