Nonparametric estimation of the mixing density using polynomials

We consider the problem of estimating the mixing density $f$ from $n$ i.i.d. observations distributed according to a mixture density with unknown mixing distribution. In contrast with finite mixtures models, here the distribution of the hidden variable is not bounded to a finite set but is spread out over a given interval. We propose an approach to construct an orthogonal series estimator of the mixing density $f$ involving Legendre polynomials. The construction of the orthonormal sequence varies from one mixture model to another. Minimax upper and lower bounds of the mean integrated squared error are provided which apply in various contexts. In the specific case of exponential mixtures, it is shown that the estimator is adaptive over a collection of specific smoothness classes, more precisely, there exists a constant A\textgreater{}0 such that, when the order $m$ of the projection estimator verifies $m\sim A \log(n)$, the estimator achieves the minimax rate over this collection. Other cases are investigated such as Gamma shape mixtures and scale mixtures of compactly supported densities including Beta mixtures. Finally, a consistent estimator of the support of the mixing density $f$ is provided

Financial Literacy and Private Old-age Provision in Germany

The German population has good financial knowledge measured on the basis of three financial literacy questions. Around 85 % of the individuals comprehend the functioning of interest and inflation. And 60 % of the individuals understand the relationship of risk and diversification. Overall around 52 % of the individuals give correct answers to all three considered ques-tions of financial literacy. Bi-variate and multivariate analyses of the relation between giving three correct answers and socio-demographic characteristics reveal that higher wealth is asso-ciated with higher levels of financial literacy. Moreover, financial literacy relates to higher levels of income and education. There is a significant difference between men and women to give three correct answers. Individuals in East and West, are equally literate, when controlling for differences in income, wealth and education. A positive correlation of financial literacy and financial decision making is identified: more literate households are more likely to save privately for their old-age and at the same time households saving privately for their old-age acquire financial knowledge to improve their investment decisions. Interestingly, the possession of a state subsidised Riester contract is related to lower levels of financial literacy than the possession of other non-subsidised forms of private old-age provision. This indicates that Riester subsidies to some extent successfully encourage individuals with lower financial knowledge to save for old-age. Nevertheless, individuals in the lowest income quintile still have very low levels of private coverage despite the high subsidies. At the same time they show the lowest levels of financial literacy.

Television program avoidance and personality

Recent communication research indicates that approach and avoidance constitute two separate yet co-existing processes during media exposure. While many studies address TV approach behavior, little is known about TV avoidance behavior. Furthermore, personality has yet to be linked to avoidance behavior. This study analyzes the influence of personality on TV program avoidance. Data show that the "Big Five" personality characteristics (Neuroticism, Extraversion, Openness, Conscientiousness, Agreeableness) and Risk and Fight Willingness influence program avoidance, albeit to varying degrees. While the specific correlations are discussed in the paper, the results generally reveal that the combination of personality and avoidance has added value in terms of understanding of TV using behavior compared to the frequently analyzed link between personality and approach. For nearly all personality characteristics, data show that the avoidance perspective is more than the inversion of the approach perspective. The findings are discussed with reference to gratification and selectivity research

A semiparametric extension of the stochastic block model for longitudinal networks

To model recurrent interaction events in continuous time, an extension of the stochastic block model is proposed where every individual belongs to a latent group and interactions between two individuals follow a conditional inhomogeneous Poisson process with intensity driven by the individuals' latent groups. The model is shown to be identifiable and its estimation is based on a semiparametric variational expectation-maximization algorithm. Two versions of the method are developed, using either a nonparametric histogram approach (with an adaptive choice of the partition size) or kernel intensity estimators. The number of latent groups can be selected by an integrated classification likelihood criterion. Finally, we demonstrate the performance of our procedure on synthetic experiments, analyse two datasets to illustrate the utility of our approach and comment on competing methods

OMP-type Algorithm with Structured Sparsity Patterns for Multipath Radar Signals

A transmitted, unknown radar signal is observed at the receiver through more than one path in additive noise. The aim is to recover the waveform of the intercepted signal and to simultaneously estimate the direction of arrival (DOA). We propose an approach exploiting the parsimonious time-frequency representation of the signal by applying a new OMP-type algorithm for structured sparsity patterns. An important issue is the scalability of the proposed algorithm since high-dimensional models shall be used for radar signals. Monte-Carlo simulations for modulated signals illustrate the good performance of the method even for low signal-to-noise ratios and a gain of 20 dB for the DOA estimation compared to some elementary method

Who lost the most? Financial literacy, cognitive abilities, and the financial crisis

We study how and to what extent private households are affected by the recent financial crisis and how their financial decisions are influenced by this shock. Our analysis reveals that individuals with low levels of financial literacy are less likely to have invested in the stock market and thus are less likely to report losses in wealth. Yet, individuals with low financial literacy are more likely to sell their assets which lost in value (realize losses). This reaction to short-term losses has potential long-term consequences if individuals do not participate in markets' recovery and face lower returns in the long run. JEL Classification: D91, D14, G11cognitive ability, financial crisis, financial literacy, life-cycle savings, Portfolio Choice, saving behavior

Who lost the most? Financial Literacy, Cognitive Abilities, and the Financial Crisis --- forthcoming Review of Finance ----

We study how and to what extent private households are affected by the recent financial crisis and how their financial decisions are influenced by this shock. Our analysis reveals that individuals with low levels of financial literacy are less likely to have invested in the stock market and thus are less likely to report losses in wealth. Yet, individuals with low financial literacy are more likely to sell their assets which lost in value (realize losses). This reaction to short-term losses has potential long-term consequences if individuals do not participate in markets' recovery and face lower returns in the long run.

Financial literacy and retirement planning in Germany

We examine financial literacy in Germany using data from the SAVE survey. We find that knowledge of basic financial concepts is lacking among women, the less educated, and those living in East Germany. In particular, those with low education and low income in East Germany have little financial literacy compared to their West German counterparts. Interestingly, there is no gender disparity in financial knowledge in the East. In order to investigate the nexus of causality between financial literacy and retirement planning we develop an IV strategy by making use of regional variation in the financial knowledge of peers. We find a positive impact of financial knowledge on retirement planning.