We analyze the impact of obsolescence of economic inventions by incorporating maintenance costsin the endogenous growth model of expanding product varieties. This contrasts with the existingliterature, which ignores maintenance costs and uses the model of quality improvements todescribe...

Which signals are important in gaining attention in science? For a group of 1,371 scientific articles published in 17 demography journals in the years 1990-1992 we track their influence and discern which signals are important in receiving citations. Three types of signals are examined: the...

This discussion paper resulted in a publication in the <A href="http://www.sciencedirect.com/science/article/pii/S0167629614001180">'Journal of Health Economics'</A> 2015, 39, 17-30.<P> This is the first study to analyze effects of in utero exposure to the severe Dutch Hunger Winter famine (1944/45) on labor market outcomes and hospitalization. This famine is clearly demarcated...</p></a>

This paper examines the effect of differences in ability on the timing and number ofchildren. Higher skilled women have less disutility of labor and have relatively lessutility of raising children. Motherhood has a negative effect on the accumulation ofhuman capital by learning-by-doing and...

We extend Lazear’s theory of skills variety and entrepreneurship in three directions. First, we provide a theoretical framework linking new business creation with an entrepreneur’s skill variety. Second, in this model we allow for both generalists and specialists to possess skill variety....

This paper investigates the relation between human capital andretirement when the age of retirement is endogenous. This relation isexamined in a life-cycle earnings model. An employee works full timeuntil retirement. The worker accumulates human capital by training-on-the-job and by...

Although the literature on the effectiveness of child care centers in developing countries is thin, most of the studies have concluded that the provision of these services are beneficial to enhance the development of poor children at early ages. Using different matching techniques, the results...

Using a discontinuity in the funding scheme, we evaluate the impact of home visitsand child care centers on poor children and mothers in Ecuador. We find thathome visits are beneficial for children's cognitive outcomes and health and for mothers'psychological well-being but reduce mothers' labor...

Over the period 2005-2009 the Dutch government increased childcare subsidies substantially, reducing the average effective parental fee by 50%, and extended subsidies to so-called guestparent care. We estimate the labour supply effect of this reform with a difference-in-differences strategy,...

This discussion paper resulted in a publication in <I>Structural Change and Economic Dynamics</I>, 2013, 24, 141-156.<P> We address the notion of dynamic, endogenous diversity and its role in theories of investment and technological innovation. We develop a formal model of an innovation arising from the...</p></i>