Job search periods for welfare applicants:Evidence from a randomized experiment

We combine a randomized experiment with administrative data to study the effects of mandatory job search periods in the Dutch welfare system. Job search periods postpone the first welfare benefits payment and encourage applicants to start searching for jobs actively. Job search periods substantially reduce benefits take up. The decline in benefits receipt is permanent, but fully compensated by increased earnings because of higher reemployment rates. We do not find detectable effects on health and crime outcomes, nor do we observe income declines for more vulnerable applicants. Our results suggest that job search periods are an effective instrument for targeting benefits to welfare applicants

Caseworker's discretion and the effectiveness of welfare-to-work programs

In this paper we focus on the role of caseworkers in the assignment and take-up of welfare-to-work programs. We conduct a field experiment that generates exogenous variation in the assignment of caseworkers to different policy regimes. The experiment allows us to provide evidence on the effectiveness of welfare-to-work programs and to study how caseworkers exploit their discretion in assigning these programs to welfare recipients. We find substantial heterogeneity in how caseworkers assign welfare-to-work programs. Participation in the experiment and learning about the effectiveness of the different programs do not induce caseworkers to focus more on the effective programs. Obtaining knowledge about welfare-to-work programs is thus not enough to improve policy, also effort on implementation is required

Field of study and partner choice

© 2021There is strong assortative mating by field of study. To examine to which extent this is due to self selection or to a causal effect of access to specific ”marriage markets”, we use data from participants in admission lotteries of four oversubscribed studies in the Netherlands. For each of the four studies, we find that the winning compliers of an admission lottery are significantly more likely than the losing compliers to have a partner from the lottery study, whereas losing compliers are only marginally more likely to have a partner from the lottery study than would occur under random matching. These results indicate that assortative mating by field of study is largely due to marriage market access and that self selection plays a minor role. JEL-codes: I26, J12, J13

How Assortment Variety Affects Assortment Attractiveness: A Consumer Perspective

Variëteit is overal aanwezig. Telkens weer moeten mensen kiezen uit een enorme hoeveelheid mogelijkheden. Waarderen consumenten zoveel variëteit eigenlijk wel in al de keuzes die ze moeten maken? Dit proefschrift levert inzichten in de relatie tussen de hoeveelheid variëteit in het assortiment van een retailer en hoe aantrekkelijk de consument dit assortiment vindt. Op basis van een rijke hoeveelheid experimentele data onthult dit proefschrift de effecten van variëteit maar ook de onderliggende processen, namelijk de voor- en nadelen van variëteit. De relatie is onderzocht voor verschillende typen assortimenten en koopsituaties. Uit het proefschrift blijkt hoe de invloed van de grootte van een assortiment op haar aantrekkelijkheid afhankelijk is van de complexiteit van de producten. Daarnaast demonstreren diepgaande analyses de rol van percepties van variëteit en de voordelen ervan. Bovendien wordt uit de analyses duidelijk dat hoewel er verschillende kosten van variëteit zijn, er maar een paar een assortiment minder aantrekkelijk maken. Voor alle typen assortimenten geldt dat een gebrek aan overzicht schadelijk is. Bij assortimenten van complexe producten geldt daarnaast dat consumenten geen spijt over hun keuze willen anticiperen, omdat dat hun waardering van het assortiment verlaagt.Variety is abundant in many different areas. Over and over again, people have to choose from huge amounts of possibilities. However, do consumers actually value the high variety presented to them for all the choices they have to make? This thesis provides insights into the relationship between the amount of variety in a retailer’s assortment and how attractive the assortment is from a consumer’s point of view. Based on a rich quantity of experimental data it uncovers the overall effects of assortment variety as well as the underlying processes, i.e., the perceived benefits and costs of variety. The relationship is examined across different types of assortments and buying situations. The thesis demonstrates how the impact of the size of an assortment on its attractiveness depends on the complexity of the products involved. Further, in-depth analyses reveal the role of consumer perceptions of variety and the benefits of variety. Moreover, they show that although variety leads to multiple costs of variety, only a few of them make an assortment less appealing. In all types of assortments, a lack of overview is damaging. For complex products only, anticipated regret of making the wrong choice is critical, since this too lowers assortment evaluations

e+e−e^{+}e^{-} pairs from a nuclear transition signaling an elusive light neutral boson

Electron-positron pairs have been observed in the 10.95-MeV $0^-\to0^+$ decay in $^{16}$O. The branching ratio of the e$^+$e$^-$ pairs compared to the 3.84-MeV $0^-\to2^+$ $\gamma$ decay of the level is deduced to be $20(5)\times10^{-5}$. This magnetic monopole (M0) transition cannot proceed by $\gamma$-ray decay and is, to first order, forbidden for internal pair creation. However, the transition may also proceed by the emission of a light neutral $0^{-}$ or $1^{+}$ boson. Indeed, we do observe a sharp peak in the $e^{+}e^{-}$ angular correlation with all the characteristics belonging to the intermediate emission of such a boson with an invariant mass of 8.5(5) MeV/c$^2$. It may play a role in the current quest for light dark matter in the universe.Comment: 6 page

Equilibrium Statistics of Weakly Slip-Linked Gaussian Polymer Chains

We calculate the free energy and the pressure of a weakly slip-linked Gaussian polymer chains. We show that the equilibrium statistics of a slip-linked system is different from one of the corresponding ideal chain system without any constraints by slip-links. It is shown that the pressure of a slip-linked system decreases compared with the ideal system, which implies that slip-linked chains spontaneously form aggregated cluster like compact structures. These are qualitatively consistent with previous theoretical analyses or multi chain simulations. We also show that repulsive potentials between chains, which have been phenomenologically utilized in simulations, can cancel the artificial pressure decrease.Comment: 24 pages, 3 figures, to appear in J. Polym. Sci. B: Polym. Phy

Numerical implementation of the exact dynamics of free rigid bodies

In this paper the exact analytical solution of the motion of a rigid body with arbitrary mass distribution is derived in the absence of forces or torques. The resulting expressions are cast into a form where the dependence of the motion on initial conditions is explicit and the equations governing the orientation of the body involve only real numbers. Based on these results, an efficient method to calculate the location and orientation of the rigid body at arbitrary times is presented. This implementation can be used to verify the accuracy of numerical integration schemes for rigid bodies, to serve as a building block for event-driven discontinuous molecular dynamics simulations of general rigid bodies, and for constructing symplectic integrators for rigid body dynamics.Comment: Shortened paper with updated references, 28 pages, 3 figure