Credibly Identifying Social Effects: Accounting for Network Formation and Measurement Error

Understanding whether and how connections between agents (networks) such as declared friendships in classrooms, transactions between firms, and extended family connections, influence their socio-economic outcomes has been a growing area of research within economics. Early methods developed to identify these social effects assumed that networks had formed exogenously, and were perfectly observed, both of which are unlikely to hold in practice. A more recent literature, both within economics and in other disciplines, develops methods that relax these assumptions. This paper reviews that literature. It starts by providing a general econometric framework for linear models of social effects, and illustrates how network endogeneity and missing data on the network complicate identification of social effects. Thereafter, it discusses methods for overcoming the problems caused by endogenous formation of networks. Finally, it outlines the stark consequences of missing data on measures of the network, and regression parameters, before describing potential solutions

A simultaneous approach to the estimation of risk aversion and the subjective time discount rate

In this paper we analyze a sample of 1832 individuals who responded to six randomly generated lottery questions that differ with respect to chance, prize and the timing of the draw. Using a model that explicitly allows for consumption smoothing, we obtain an estimate of relative risk aversion of 82. Instead, assuming consumption to be immediate gives an estimate of 2, close to what is traditionally reported, while a model of full asset integration gives estimates higher by several orders of magnitude. Our results show that estimated risk aversion is sensitive to the assumptions made with respect to the consumption profile and that it is possible to determine the level of asset integration endogenously. The average subjective time discount rate, which includes a preference for the present, equals 6 percent per month. It is found that both parameters vary strongly over individuals and that the variation can be explained by income, age, gender, and entrepreneurship, consistent with the majority of previous evidence. Keywords: Expected utility; Asset integration; Risk aversion; Time preference; Lotteries; Hypothetical questions JEL classification codes: D12; D80; D90; E2

Ability Peer Effects in University: Evidence from a Randomized Experiment

This article estimates peer effects originating from the ability composition of tutorial groups for undergraduate students in economics. We manipulated the composition of groups to achieve a wide range of support, and assigned students—conditional on their prior ability—randomly to these groups. The data support a specification in which the impact of group composition on achievement is captured by the mean and standard deviation of peers’ prior ability, their interaction, and interactions with students’ own prior ability. When we assess the aggregate implications of these peer effects regressions for group assignment, we find that low- and medium-ability students gain on an average 0.19 SD units of achievement by switching from ability mixing to three-way tracking. Their dropout rate is reduced by 12 percentage points (relative to a mean of 0.6). High-ability students are unaffected. Analysis of survey data indicates that in tracked groups, low-ability students have more positive interactions with other students, and are more involved. We find no evidence that teachers adjust their teaching to the composition of groups

A parameter-free analysis of the utility of money for the general population under prospect theory

Extensive data has convincingly demonstrated that expected utility, the reigning economic theory of rational decision making, fails descriptively. This descriptive failure casts doubt on the validity of classical utility measurements. Prospect theory can better explain choice behaviour because it makes the plausible assumption that risk attitudes are not only driven by sensitivity towards outcomes (utility curvature), but also by sensitivity towards probabilities (probability weighting), and by sensitivity towards whether outcomes are above or below a reference point (loss aversion). This paper presents an experiment that completely measures the utility- and loss aversion component of risk attitudes, using a representative sample of NÂ =Â 1935 respondents from the general public, in a parameter-free way. This study thereby provides the first measurement of the utility of money for the general population that is valid under (cumulative) prospect theory, does not depend on prior assumptions about the underlying functional form of utility, is externally valid, and does not rule out heterogeneity of individual preferences. The results confirm the concave-convex pattern of utility as predicted by prospect theory, suggest that utility curvature is less pronounced than suggested by classical utility measurements, and show that women are significantly more loss averse than men

The role of information in the take-up of student loans

We study student loan behavior in the Netherlands where (i) higher education students know little about the conditions of the government's financial aid program and (ii) take-up rates are low. In a field experiment we manipulated the amount of information students have about these conditions. The treatment has no impact on loan take-up, which is not due to students already having decided to take a loan or students not absorbing the information. We conclude that a lack of knowledge about specific policy parameters does not necessarily imply a binding information constraint