HIV testing,subjective beliefs and economic behavior

This paper examines the effects of learning HIV status on economic behavior among rural Malawians. According to economic life-cycle models, if learning HIV results is informative about additional years of life, being diagnosed HIV-positive or negative should predict changes in consumption, investment and savings behavior with important micro and macro-economic implications. Using an experiment that randomly assigned incentives to learn HIV results, I find that while learning HIV results had short term effects on subjective belief of HIV infection, these differences did not persist after two years. Consistent with this, there were relatively few differences two years later in savings, income, expenditures, and employment between those who learned and did not learn their status.     

The Demand for, and Impact of, Learning HIV Status

This paper evaluates an experiment in which individuals in rural Malawi were randomly assigned monetary incentives to learn their HIV results after being tested. Distance to the HIV results centers was also randomly assigned. Without any incentive, 34 percent of the participants learned their HIV results. However, even the smallest incentive doubled that share. Using the randomly assigned incentives and distance from results centers as instruments for the knowledge of HIV status, sexually active HIV-positive individuals who learned their results are three times more likely to purchase condoms two months later than sexually active HIV-positive individuals who did not learn their results; however, HIV-positive individuals who learned their results purchase only two additional condoms than those who did not. There is no significant effect of learning HIV-negative status on the purchase of condoms.     

Tax evasion and tax morale: A social network analysis

We study the effects of tax morale and social norms on tax evasion when individuals interact in a network. We present a model that incorporates incentives for tax compliance in the form of punishment and fines, tax morale, and reputation for social behaviour. We assume that individuals adjust their tax morale by observing the neighbours' tax morale. We simulate the model for different values of the parameters and show that the steady-state share of taxpayers as opposed to tax-evaders is affected by the probability of finding like-minded peers in the reference group (network integration), the weight that individuals attribute to reputation, and the share of individuals who update their tax morale. Last, we consider the possibility of a fiscal authority using the knowledge of the network structure and targeting ‘central’ individuals. We show that by positively affecting the tax morale of individuals whose influence within the network is high, a fiscal authority can increase tax compliance.     

The opportunity cost of social relations: On the effectiveness of small worlds

The aim of this paper is to extend the theoretical literature on knowledge and network structure by studying the use of social networks as a learning mechanism. The novelty of this approach is suggested by the empirical evidence on informal trading of know-how. In the model, we consider a set of actors who create and diffuse knowledge with the aim of increasing their own personal knowledge. They are located on a lattice (identifying the social space) and are directly connected to a small number of other individuals. We assume that individuals can learn individually or socially, and that individuals choose how to learn on the basis of a cost-benefit comparison. Within this framework, we compare network structures in terms of efficiency and equity. We find that the opportunity cost of using the network affects its optimal structure in terms of aggregate performance and that the small world does not emerge unambiguously as being the most efficient.     

Learning by investing

We test for learning among heterogeneous individuals who are engaged in bidding and who possess limited information about the auctioned assets. We use an extensive dataset taken from an auction through which state‐owned enterprises were privatized in the Czech Republic in 1993–94. To test for learning, we develop new measures of individual performance to accommodate the varying prices of assets available in six successive stages of bidding. We present evidence that learning took place among heterogeneous agents during a large‐scale multi‐stage auction that is unique in terms of its size, incentives and variation. The auction’s design, with multiple market periods, allowed agents to learn based on accumulated experience. As individuals had to pay a fee to participate, and as the potential gain was in the magnitude of several months’ salary, we conclude that large incentives were driving our results.     

Productivity drivers of infrastructure companies: Network industries utilizing economies of scale in the digital era

What drives the productivity dynamics of infrastructure companies? Using a panel of firms in 14 countries, we study total factor productivity (TFP) enhancers of utility and network services companies. We find that moving TFP closer to the technological frontier drives productivity growth at higher speeds in Asian countries than in European countries. We also find that financial leverage exerts a positive effect on TFP growth for larger infrastructure firms and that more financially developed countries utilize economies of scale through better use of financial resources. Large utility and transportation companies display a higher rate of TFP growth, indicating that a competition policy to encourage M&As would be prudent for the utility/transportation sectors to maximize economies of scale. In contrast, we find diseconomies of scale for energy companies in some countries. Moreover, young network firms improve TFP growth faster than their peers in countries with fewer product market regulations. Therefore, policies should remove entry barriers while facilitating the departure of old and low-productivity firms from network markets. Finally, policymakers should offer well-targeted fiscal incentives for intangible investments to boost TFP because the accumulation of intangible assets such as digital technology promotes more scale economies through network effects.     

How helpful are social networks in finding a job along the economic cycle? Evidence from immigrants in France

Around 50% of individuals obtain or hear about jobs through social networks. This hiring trend may become problematic when the labor market is tight and people need less social contacts to find a job. Using a one-period static model where network members may receive job offers directly from the firm or indirectly through employed members in the network we show that the share of new hires finding a job through social connections (ie network matching rate) decreases with the job finding rate. Using French data for the period 2003–2012, we test this prediction with immigrants, a population subgroup for whom networks play a major role in occupational decisions. We propose two network matching rate indicators, one based on direct recommendations and another one internalizing the positive externality on the employment probability induced by peers. We find a decreasing relationship between the network matching rate and the job finding rate. Social connections are less helpful for finding jobs during economic expansions.     

Risk taking under heterogenous revenue sharing

We examine the impact of informal risk sharing on risk taking incentives when transfers are organized through a social network. A bilateral partial sharing rule satisfies that neighbors share equally a part of their revenue. In such a society, correlated technologies generate interdependent risk levels. We obtain three findings. First, there is a unique and interior Nash-equilibrium risk profile, and it is in general differentiated and related to the Bonacich measure of the risk sharing network. Second, more revenue sharing enhances risk taking on average, although some agents may lower their risk level. Last, we find that under investment might often be observed.     

The strength of weak ties in crime

The aim of this paper is to investigate whether weak ties play an important role in explaining criminal activities. We first develop a model where individuals learn about crime opportunities by interacting with other peers. These interactions can take the form of either strong or weak ties. We find that increasing the percentage of weak ties induces more transitions from non-crime to crime and thus the crime rate in the economy increases. This is because, when the percentage of weak ties is high, delinquents and non-delinquents are in close contact with each other. We then test these predictions using the U.S. National Longitudinal Survey of Adolescent Health (AddHealth), which contains unique detailed informations on friendship relationships among teenagers. The theoretical predictions of our model are confirmed by the empirical analysis since we find that weak ties, as measured by friends of friends, have a positive impact on criminal activities.     

Misery loves company: Social regret and social interaction effects in choices under risk and uncertainty

Extensive field evidence shows individuals? decisions in settings involving uncertainty depend on their peers? decisions. One hypothesized cause of peer group effects is social interaction effects: an individual?s utility from an action is enhanced by others taking the same action. We employ a series of controlled laboratory experiments to study the causes of peer effects in choice under uncertainty. We find strong peer group effects in the laboratory. Our design allows us to rule out social learning, social norms, group affiliation, and complementarities as possible causes for the observed peer group effects, leaving social interaction effects as the likely cause. We use a combination of theory and empirical analysis to show that preferences including “social regret” are more consistent with the data than preferences including a taste for conformity. We observe spillover effects, as observing another?s choice of one risky gamble makes all risky gambles more likely to be chosen.     

Showing off to the new neighbors? Income,socioeconomic status and consumption patterns of internal migrants

This paper analyses incomes and socioeconomic status of internal migrants over time and in comparison to their new neighbors and investigates whether status consumption is a way for newly arrived city dwellers to signal their social standing. Using a novel dataset from the emerging economy of Kazakhstan we find that internal migrants earn an income and status premium for their move. In a comparison to indigenous city dwellers their earnings and household incomes are not significantly different; however, mobile households report a significantly higher subjective socio-economic status. Exploiting expenditure data, we find that recent migrant households gain status from using visible consumption to impress their new neighbors. This signaling might be used as adaptation to the new economic and social environment or to gain access to social capital.     

Investment risk taking by institutional investors

According to theory, institutional investors face both risk-management and risk-shifting incentives. This article assesses the relevance of these conflicting incentives for Dutch pension funds and insurance firms over the period 1995 to 2009. Using a unique and extended data set, we observe a significant positive relationship between capital and asset risk for insurers, indicating that risk-management incentives dominate in the Dutch insurance industry. Risk-shifting incentives, however, also seem relevant, as stock insurers take more investment risk than their mutual peers. For Dutch pension funds, we conclude that overall neither risk-shifting nor risk-management incentives seem to dominate. Interestingly, we find that professional group pension funds take significantly less investment risk than other types of pension funds. This finding is in line with expectations, as in professional group pension funds potential incentive conflicts between pension fund participants and the employer are effectively internalized.     

PRIVATE PROVISION OF PUBLIC GOODS AND INFORMATION DIFFUSION IN SOCIAL GROUPS

I describe a dynamic model of costly information sharing where private information affecting collective‐value actions is transmitted by social proximity. Individuals make voluntary contributions toward the provision of a pure public good, and information transmission about quality of provision is a necessary condition for collective provision to take place in a stationary equilibrium. I show that unlike in the case of private goods, better informed individuals face positive incentives to incur a cost to share information with their neighbors and that these incentives are stronger and provision of the pure public good greater the smaller are individuals' social neighborhoods.     

Subsidized temporary jobs: lock-in and stepping stone effects

This article evaluates the effectiveness of subsidized temporary jobs as stepping stones to regular employment. We study a French program that allows job seekers to work part-time while remaining registered with the unemployment agency. In this program, insured individuals concurrently receive part of their unemployment benefits and wage income. Using administrative data, we find that subsidized temporary jobs have both a significant lock-in effect and a significant positive post-treatment impact on the hazard rate to employment. Since individuals facing a high implicit tax rate have incentives to self-select into better part-time jobs, we also find that a higher tax rate leads to a weaker lock-in effect and a stronger post-treatment effect. Simulations suggest that the lock-in effect first dominates, but that the overall effect eventually becomes positive. They also point to ways of improving the effectiveness of the policy.     

Does peer group size influence social preferences and risk taking?

This paper examines whether the ex post relative payoffs of peers as well as the size of the peer group impact an agent's willingness to take risks. For example, persons in a flood plain may be less likely to purchase flood insurance if their neighbors also refrain from purchasing. We generalize the Fehr‐Schmidt (1999) model to allow the intensity of the social preferences to vary with the size of the peer group. Our experiment tests whether subjects are more or less likely to choose a lottery over a fixed payment when others have been assigned either the same lottery or the fixed payment. Using both between and within subject designs, we find risk‐taking behaviour is not responsive to the risks faced by others regardless of the size of peer group.     

Social integration and subjective wellbeing

Using data from the UK Community Life Survey, we examine the relationship between social integration and subjective wellbeing. We measure social integration along various dimensions, including frequency of interaction with one’s neighbors, perceived strength of belonging to one’s immediate neighborhood and country, length of residence in a neighborhood, and trust in neighbors. Overall, we find that social integration is associated with higher levels of subjective wellbeing. Specifically, our results suggest that an increase in the frequency of interaction with one’s neighbors is associated with an increase in subjective wellbeing. Similarly, an increase in respondent’s perceived strength of belonging to their immediate neighborhood (and country) is associated with an increase in subjective wellbeing. We further discover that an increase in the length of residence in a neighborhood is associated with an increase in subjective wellbeing, and this is also the case for an increase in the level of trust in one’s neighbour.     

Social learning,neighborhood effects,and investment in human capital: Evidence from Green-Revolution India

This paper empirically identifies social learning and neighborhood effects in schooling investments in a new technology regime. Social learning implies that learning is most efficient when observed heterogeneity in schooling is greatest. The estimates of learning-investment rule, from farm household panel data at the onset of the Green Revolution in India, show that (i) agents learn about schooling returns from income realizations of their neighbors, and (ii) the speed of learning is high when the variation of schooling is large. Thus, schooling distribution of the parents' generation in a community has externalities to schooling investments in children. Simulations show that the variations in schooling within and across communities generate variations in child enrollment rate and average household income.     

Income inequality, consumption, and social-status seeking

Using the Chinese Urban Household Survey data between 1997 and 2006, we find that income inequality has a negative (positive) effect on household consumption net of education expenditures (savings) even after we control for household income. We argue that people save to improve their social status when social status is associated with pecuniary and non-pecuniary benefits. Rising income inequality can strengthen the incentives of status-seeking savings by increasing the benefit of improving status, and by enlarging the wealth level required for status upgrading. We also find that the negative effect of income inequality on consumption is stronger for poorer and younger people and that income inequality stimulates more education investment, which are consistent with the status-seeking hypothesis.     

Heterogeneous treatment effects and mechanisms in information-based environmental policies: Evidence from a large-scale field experiment

Policymakers often rely on non-pecuniary, information-based programs to achieve social objectives. Using data from a water conservation information campaign implemented as a randomized controlled trial, we estimate heterogeneous household responses. Understanding such heterogeneity is important for improving the cost-effectiveness of non-pecuniary programs, extending them to other populations and probing the mechanisms through which the treatment effects arise. We find little evidence of heterogeneous responses to purely technical information or to traditional conservation messages that combine technical information and moral suasion. In contrast, norm-based messages that combine technical information, moral suasion and social comparisons exhibit strong heterogeneity: households that are wealthier, owner-occupied and use more water are more responsive. These subgroups tend to be least responsive to pecuniary incentives. We find no evidence that any subgroup increases their water use in response to the messages. By targeting the messages to subgroups known to be most responsive, program costs could be reduced by over 50% with only a 20% reduction in the treatment effect. Combining theory and data, we also shed light on the mechanisms through which the treatment effects arise, which has implications for program design and future research on the program's welfare effects.     

The effect of self-employed health insurance subsidies on self-employment

This paper estimates the effect of an increase in the deductibility of health insurance premiums for self-employed individuals on the probability of being self-employed. Using a panel of tax returns from 1999 to 2004, we estimate fixed effects instrumental variable regressions for the probability of being self-employed, entering into self-employment, and exiting from self-employment. Our results suggest that this policy increased the probability of being self-employed by 1.5 percentage points, and increased the probability that a taxpayer would be primarily or exclusively self-employed by 1.1 and 0.35 percentage points respectively. These effects explain about a third to a half of the total increase in self-employment by these definitions over the sample period. We also find that the probability of entering self-employment increased by 0.8 percentage points and find suggestive evidence that the probability of exit decreased by 2.8 percentage points.