Is Self-Employment Always a Bad Experience?

We estimate the effects of past self-employment experience on subsequent earnings in wage work using the population of Danish citizens between 16 and 65 years of age that we observe between 1980 and 1996. Specifically, we analyze how the effects of previous self-employment experience are affected by age, success in self-employment and the employment status prior to self-employment. We also take a long-term perspective and test whether wage-effects of self-employment are nonlinear and if they depreciate over time. We find that an additional year of self-employment experience reduces subsequent wage earnings by 4.7%-8.2% compared to continued wage-work experience. Young and successful formerly self-employed benefit, however, from their self-employment experience. Moreover, formerly self-employed who were non-employed or unemployed prior to their self-employment experience receive only slightly lower wages than individuals that never entered self-employment. We also find that the negative self-employment effects decrease with longer spells of self-employment and that they depreciate over time in subsequent wage work.self-employment; entrepreneurship; wages; experience

Entrepreneurship, Job Creation, and Wage Growth

This paper analyses the importance of entrepreneurs for job creation and wage growth. Relying on unique data that cover all establishments, firms and individuals in the Danish private sector, we are able to distil a number of different subsets from the total set of new establishments – subsets which allow us to more precisely capture the "truly new" or "entrepreneurial" establishments than in previous studies. Using these data, we find that while new establishments in general account for one third of the gross job creation in the economy, entrepreneurial establishments are responsible for around 25% of this, and thus only account for about 8% of total gross job creation in the economy. However, entrepreneurial establishments seem to generate more additional jobs than other new establishments in the years following entry. Finally, the jobs generated by entrepreneurial establishments are to a large extent low-wage jobs, as they are not found to contribute to the growth in average wages.job creation; entrepreneurial establishments; wage growth

Do Foreign Experts Increase the Productivity of Domestic Firms?

While most countries welcome (and some even subsidise) high-skilled immigrants, there is very limited evidence of their importance for domestic firms. To guide our empirical analysis, we first set up a simple theoretical model to show how foreign experts may impact on the productivity and wages of domestic firms. Using matched worker-firm data from Denmark and a difference-indifferences matching approach, we then find that firms that hire foreign experts – defined as employees eligible for reduced taxation under the Danish "Tax scheme for foreign researchers and key employees" – both become more productive (pay higher wages) and increase their exports of goods and services.foreign experts, export, immigrants, productivity, difference-in-differences matching

A users manual for a computer program which calculates time optical geocentric transfers using solar or nuclear electric and high thrust propulsion

This manual is a guide for using a computer program which calculates time optimal trajectories for high-and low-thrust geocentric transfers. Either SEP or NEP may be assumed and a one or two impulse, fixed total delta V, initial high thrust phase may be included. Also a single impulse of specified delta V may be included after the low thrust state. The low thrust phase utilizes equinoctial orbital elements to avoid the classical singularities and Kryloff-Boguliuboff averaging to help insure more rapid computation time. The program is written in FORTRAN 4 in double precision for use on an IBM 360 computer. The manual includes a description of the problem treated, input/output information, examples of runs, and source code listings

Air-breathing hypersonic vehicle guidance and control studies; An integrated trajectory/control analysis methodology: Phase 1

A tool which generates optimal trajectory/control histories in an integrated manner is generically adapted to the treatment of single-stage-to-orbit air-breathing hypersonic vehicles. The methodology is implemented as a two point boundary value problem solution technique. Its use permits an assessment of an entire near-minimum-fuel trajectory and desired control strategy from takeoff to orbit while satisfying physically derived inequality constraints and while achieving efficient propulsive mode phasing. A simpler analysis strategy that partitions the trajectory into several boundary condition matched segments is also included to construct preliminary trajectory and control history representations with less computational burden than is required for the overall flight profile assessment. A demonstration was accomplished using a tabulated example (winged-cone accelerator) vehicle model that is combined with a newly developed multidimensional cubic spline data smoothing routine. A constrained near-fuel-optimal trajectory, imposing a dynamic pressure limit of 1000 psf, was developed from horizontal takeoff to 20,000 ft/sec relative air speed while aiming for a polar orbit. Previously unspecified propulsive discontinuities were located. Flight regimes demanding rapid attitude changes were identified, dictating control effector and closed-loop controller authority was ascertained after evaluating effector use for vehicle trim. Also, inadequacies in vehicle model representations and specific subsystem models with insufficient fidelity were determined based on unusual control characteristics and/or excessive sensitivity to uncertainty

Foreign Firms, Domestic Wages

Many papers have documented a wage premium in foreign-owned and large firms. However, there is very little formal theory in the literature and empirical analyses are typically not based on hypotheses which are rigorously derived from theory. This paper contributes to the theory-empirics gap by developing a model that allows for two “pure” explanations for the wage premium. The first is a heterogenous-worker explanation along the lines of Yeaple (2005), where firms that select more scaleintensive technologies select ex-ante more productive workers. In this case, the wage premium is a pure selection phenomenon. The second explanation builds on the heterogeneous-firm model of Melitz (2003) combined with on-the-job learning as in Markusen (2001). Productivity differences between firms are internalized by ex-ante homogeneous workers, so the wage premium is a pure learning phenomenon due to ex-post higher productivity in foreign firms. Our model yields a number of precise empirical hypotheses. When these predictions are tested on Danish matched employer-employee data, we find that both explanations play a role in explaining the observed wage premium. Specifically, the foreign- and large-firm premiums explained by selection are in the neighborhood of 30-65% of the total premium, with the remainder consistent with learning. There is also considerable support for a number of other predictions specific to the worker-learning explanation.

Foreign Firms, Domestic Wages

Foreign-owned firms are often hypothesized to generate productivity "spillovers" to the host country, but both theoretical micro-foundations and empirical evidence for this are limited. We develop a heterogeneous-firm model in which ex-ante identical workers learn from their employers in proportion to the firm?s productivity. Foreign-owned firms have, on average, higher productivity in equilibrium due to entry costs, which means that low-productivity foreign firms cannot enter. Foreign firms have higher wage growth and, with some exceptions, pay higher average wages, but not when compared to similarly large domestic firms. The empirical implications of the model are tested on matched employer-employee data from Denmark. Consistent with the theory, we find considerable evidence of higher wages and wage growth in large and/or foreign-owned firms. These effects survive controlling for individual characteristics, but, as expected, are reduced significantly when controlling for unobservable firm heterogeneity. Furthermore, acquired skills in foreign-owned and large firms appear to be transferable to both subsequent wage work and self-employment.