Women, work, and motherhood: changing employment penalties for motherhood in West Germany after 1945 - a comparative analysis of cohorts born in 1934-1971

This paper deals with the effects of entry into motherhood on women’s employment dynamics. Our analysis is based on the complete lifetime working- and income histories of a 1% sample of all persons born between 1934 and 1971 and employed in West Germany sometime between 1975 and 1995. We use the records of women who were employed before the birth of their first child. We apply a semi-parametric hierarchical Bayesian modeling approach simultaneously including several time scales and further covariates whose effects we estimate by MCMC techniques. We investigate short-term consequences of entry into motherhood and their changes over different birth cohorts and thereby take into account the employment histories before the birth of the first child. We conduct two models differentiating between the simple return to the labor market and the return for at least a certain period in order to measure subsequent employment stability. Our results indicate that a higher extent of employment experience, a stronger attachment to the labor market and an employment in white collar jobs reduces the employment penalty for mothers after the birth of their first child.

Bound States of Non-Hermitian Quantum Field Theories

The spectrum of the Hermitian Hamiltonian ${1\over2}p^2+{1\over2}m^2x^2+gx^4$ ($g>0$), which describes the quantum anharmonic oscillator, is real and positive. The non-Hermitian quantum-mechanical Hamiltonian $H={1\over2}p^2+{1 \over2}m^2x^2-gx^4$, where the coupling constant $g$ is real and positive, is ${\cal PT}$-symmetric. As a consequence, the spectrum of $H$ is known to be real and positive as well. Here, it is shown that there is a significant difference between these two theories: When $g$ is sufficiently small, the latter Hamiltonian exhibits a two-particle bound state while the former does not. The bound state persists in the corresponding non-Hermitian ${\cal PT}$-symmetric $-g\phi^4$ quantum field theory for all dimensions $0\leq D<3$ but is not present in the conventional Hermitian $g\phi^4$ field theory.Comment: 14 pages, 3figure

Labor Market I. Data from the German Federal Employment Services

This contribution shows the increasing supply on German micro data over the last years for labor market research. We focus on the research data centre movement, the development of new anonymisation techniques for establishment data, the new challenges of the social code II and the fundamental change to evaluate labor market programmes actively with administrative data. Although a lot of ongoing developments like combining different data sets are happening, we make three recommendations for future developments in this area: (1) Demand to have an influence an the data production. (2) The need to combine data sets (especially across national borders) (3) Importance to establish an international infrastructure for data access.labor market, data access, administrative data, linked employer employee data, research data center, social code II, evaluation

PT-Symmetric Quantum Mechanics

This paper proposes to broaden the canonical formulation of quantum mechanics. Ordinarily, one imposes the condition $H^\dagger=H$ on the Hamiltonian, where $\dagger$ represents the mathematical operation of complex conjugation and matrix transposition. This conventional Hermiticity condition is sufficient to ensure that the Hamiltonian $H$ has a real spectrum. However, replacing this mathematical condition by the weaker and more physical requirement $H^\ddag=H$, where $\ddag$ represents combined parity reflection and time reversal ${\cal PT}$, one obtains new classes of complex Hamiltonians whose spectra are still real and positive. This generalization of Hermiticity is investigated using a complex deformation $H=p^2+x^2(ix)^\epsilon$ of the harmonic oscillator Hamiltonian, where $\epsilon$ is a real parameter. The system exhibits two phases: When $\epsilon\geq0$, the energy spectrum of $H$ is real and positive as a consequence of ${\cal PT}$ symmetry. However, when $-1<\epsilon<0$, the spectrum contains an infinite number of complex eigenvalues and a finite number of real, positive eigenvalues because ${\cal PT}$ symmetry is spontaneously broken. The phase transition that occurs at $\epsilon=0$ manifests itself in both the quantum-mechanical system and the underlying classical system. Similar qualitative features are exhibited by complex deformations of other standard real Hamiltonians $H=p^2+x^{2N}(ix)^\epsilon$ with $N$ integer and $\epsilon>-N$; each of these complex Hamiltonians exhibits a phase transition at $\epsilon=0$. These ${\cal PT}$-symmetric theories may be viewed as analytic continuations of conventional theories from real to complex phase space.Comment: 20 pages RevTex, 23 ps-figure

Do initial conditions persist between firms? : an analysis of firm-entry cohort effects and job losers using matched employer-employee data

"Influential studies have suggested that initial conditions can have persistent effects on workers' careers within firms. It is a longstanding question among economists whether such lasting wage differentials among firms and industries are due to persistent deviations of wages from workers' skills due to contracting and market frictions, or whether they arise from permanent differences among workers' skills. However, there is currently little representative evidence on firm-entry cohort effects and few explicit tests of alternative explanations. We use information on the universe of workers from a large German manufacturing sector from matched employer- employee records to show that firm-entry cohort effects are a pervasive phenomenon for the firms we study. The cohort effects we estimate are highly heterogeneous across firms and slowly fade over time. We also find that wage premiums on the past job are lost at job displacement, and that initial positive effects on wage levels at the new job fades over time. This suggests that at least part of firm-entry cohort effects arise from transitory rents, and that initial effects from previous wages fade as workers' search for better jobs." (Author's abstract, IAB-Doku) ((en))Kohortenanalyse, Automobilindustrie, Berufseinmündung - Auswirkungen, Berufsverlauf, Entlassungen, zwischenbetriebliche Mobilität, Arbeitskräftemobilität, Lohnentwicklung, IAB-Linked-Employer-Employee-Datensatz

FDZ annual report 2007

"Following the two evaluations by the German Council for Social and Economic Data in 2006 and by the German Council of Science and Humanities in 2007, the Research Data Centre (FDZ) of the Federal Employment Agency at the Institute for Employment Research plans to report on its activities regularly in future. We are beginning with this FDZ Annual Report 2007, which is intended to summarise the main events of the past 12 or 24 months in a few pages. The Annual Report also serves to provide transparency for our users, who after all justify the existence of the FDZ. This Report is divided into the following chapters: 'General Function', 'Basic Information', 'The Service-Oriented FDZ', 'The International FDZ' and, as an apt conclusion, 'Research at the FDZ'. Parts of the appendices (for Example Publications or Presentations in German) are not translated into English." (Text excerpt, IAB-Doku) ((en)) Additional Information Here you can find the German version of the report.Forschungsdatenzentrum - Bericht, Bundesagentur für Arbeit, IAB, amtliche Statistik, Datenzugang, Datenschutz, Arbeitsmarkt- und Berufsforschung, IAB-Beschäftigtenstichprobe, IAB-Betriebspanel, IAB-Betriebs-Historik-Panel, IAB-Linked-Employer-Employee-Datensatz, Integrierte Erwerbsbiografien, Datenaufbereitung, Datenausgabe

The wage effects of entering motherhood: a within-firm matching approach

We analyze the wage effects of employment breaks of women entering motherhood using a novel within-firm matching approach where mothers? wages upon return to the job are compared with those of their female colleagues within the same firm. Using an administrative German data set we investigate three different matching procedures based on information two years before birth: (1) exact matching on individual characteristics, (2) propensity score matching and (3) a combined procedure of exact and propensity score matching. Our results yield new insights into the nature of the wage penalty associated with motherhood, since we find first births to reduce women?s wages by 16 to 19 percent, regardless of the matching procedure applied. Neglecting the firm identifier and matching across all firms, however, yields a wage cut of 30 percent. Furthermore, we can show that the wage loss increases with the duration of the employment break. --wages,parental leave,matching

The wage effects of entering motherhood : a within-firm matching approach

"We analyze the wage effects of employment breaks of women entering motherhood using a novel within-firm matching approach where mothers' wages upon return to the job are compared with those of their female colleagues within the same firm. Using an administrative German data set we investigate three different matching procedures based on information two years before birth: (1) exact matching on individual characteristics, (2) propensity score matching and (3) a combined procedure of exact and propensity score matching. Our results yield new insights into the nature of the wage penalty associated with motherhood, since we find first births to reduce women's wages by 16 to 19 percent, regardless of the matching procedure applied. Neglecting the firm identifier and matching across all firms, however, yields a wage cut of 30 percent. Furthermore, we can show that the wage loss increases with the duration of the employment break." (Author's abstract, IAB-Doku) ((en))Mütter, Erwerbsunterbrechung, erwerbstätige Frauen, Einkommenseffekte, Lohnhöhe, Erziehungsurlaub, Elternschaft, ökonomische Faktoren, Kinderlosigkeit, Lohnunterschied, IAB-Beschäftigtenstichprobe