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2019 Working papers

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Title/Author(s) Abstract Number

News We Like to Share: How News Sharing on Social Networks Influences Voting Outcomes

Kirill Pogorelskiy
& Matthew Shum

More voters than ever get political news from their friends on social media platforms. Is this bad for democracy? Using context-neutral laboratory experiments, we find that biased (mis)information shared on social networks affects the quality of collective decisions relatively more than does segregation by political preferences on social media. Two features of subject behavior underlie this finding: 1) they share news signals selectively, revealing signals favorable to their candidates more often than unfavorable signals; 2) they naıvely take signals at face value and account for neither the selection in the shared signals nor the differential informativeness of news signals across different sources. 1199

The Dynamic Effects of Tax Audits

Arun Advani, William Elming and Jonathan Shaw

Understanding causes of and solutions to non-compliance is important for a tax authority. In this paper we study how and why audits affect reported tax in the years after audit – the dynamic effect – for individual income taxpayers. We exploit data from a random audit program covering more than 53,000 income tax self assessment returns in the UK, combined with data on the population of tax filers between 1999 and 2012. We first document that there is substantial
non-compliance in this population. One in three filers underreports the tax owed. Third party information on an income source does not predict whether a taxpayer is non-compliant on that income source, though it does predict the extent of underreporting. Using the random nature of the audits, we provide evidence of dynamic effects. Audits raise reported tax liabilities for at least five years after audit, implying an additional yield 1.5 times the direct revenue raised from the audit. The magnitude of the impact falls over time, and this decline is faster for
less autocorrelated income sources. Taking an event study approach, we further show that the change in reporting behaviour comes only from those found to have made errors in their tax report. Finally, using an extension of the Allingham-Sandmo (1972) model, we show that these results are best explained by audits providing the tax authority with information, which then constrains taxpayers’ ability to misreport.
1198

Trade Blocs and Trade Wars during the Interwar Period 

David S. Jacks and Dennis Novy

What precisely were the causes and consequences of the trade wars in the 1930s? Were there perhaps deeper forces at work in reorienting global trade prior to the outbreak of World War II? And what lessons may this particular historical episode provide for the present day? To answer these questions, we distinguish between long-run secular trends in the period from 1920 to 1939 related to the formation of trade blocs (in particular, the British Commonwealth) and short-run disruptions associated with the trade wars of the 1930s (in particular, large and widespread declines in bilateral trade, the narrowing of trade imbalances, and sharp drops in average traded distances). We argue that the trade wars mainly served to intensify pre-existing efforts towards the formation of trade blocs which dated from at least 1920. More speculatively, we argue that the trade wars of the present day may serve a similar purpose as those in the 1930s, that is, the intensification of China- and US-centric trade blocs. 1197

Testing for collusion in bus contracting in London

Michael Waterson and Jian Xie

We investigate the London bus market, a large market with regular procurement of bus services, for possible collusion using a wide variety of techniques, making use of the data at our disposal. There is little evidence of collusion in bidding for contracts apparent from our data, despite some features of the market that might lead to collusive behaviour. 1196

Search Frictions and Evolving Labour Market Dynamics

Michael Ellington,
Chris Martin and Bingsong Wang

This paper puts search frictions models under novel empirical scrutiny and tests their ability to match empirical observations. To capture changing dynamics we fit an extended Bayesian time-varying parameter VAR to US labour market data from 1962–2016. We find strong evidence against key predictions of the search frictions model, namely a large surge in vacancy creation in response to productivity shocks and a negative relationship between the volatilities of unemployment and wages. Our results question the amplification mechanism embedded in search frictions models and cast doubt on wage rigidity as a source of unemployment volatility. 1195

How to Improve Tax Compliance? Evidence from Population-wide Experiments in Belgium

Jan-Emmanuel De Neve, Clement Imbert, Johannes Spinnewijn, Teodora Tsankova & Maarten Luts

We study the impact of deterrence, tax morale, and simplifying information on tax compliance. We ran five experiments spanning the tax process which varied the communication of the tax administration with all income taxpayers in Belgium. A consistent picture emerges across experiments: (i) simplifying communication increases compliance, (ii) deterrence messages have an additional positive effect, (iii) invoking tax morale is not effective. Even tax morale messages that improve knowledge and appreciation of public services do not raise compliance. In fact, heterogeneity analysis with causal forests shows that tax morale treatments backfire for most taxpayers. In contrast, simplification has large positive effects on compliance, which diminish over time due to follow-up enforcement. A discontinuity in enforcement intensity, combined with the experimental variation, allows us to compare simplification with standard enforcement measures. Simplification is far more cost-effective, allowing for substantial savings on enforcement costs, and also improves compliance in the next tax cycle 1194

Discrimination in Hiring Based on Potential and Realized
Fertility: Evidence from a Large-Scale Field Experiment

Sascha O. Becker, Ana Fernandes and Doris Weichselbaumer

Due to conventional gender norms, women are more likely to be in charge of childcare than men. From an employer’s perspective, in their fertile age they are also at “risk” of pregnancy. Both factors potentially affect hiring practices of firms. We conduct a largescale correspondence test in Germany, Switzerland, and Austria, sending out approx. 9,000 job applications, varying job candidate’s personal characteristics such as marital status and age of children. We find evidence that, for part-time jobs, married women with older kids, who likely finished their childbearing cycle and have more projectable childcare chores than women with very young kids, are at a significant advantage vis-àvis other groups of women. At the same time, married, but childless applicants, who have a higher likelihood to become pregnant, are at a disadvantage compared to single, but
childless applicants to part-time jobs. Such effects are not present for full-time jobs, presumably, because by applying to these in contrast to part-time jobs, women signal that they have arranged for external childcare.
1193

Mostly Harmless Simulations? Using Monte Carlo Studies for Estimator Selection

Arun Advani, Toru Kitagawa and Tymon Słoczyński

We consider two recent suggestions for how to perform an empirically motivated Monte Carlo study to help select a treatment effect estimator under unconfoundedness. We show theoretically that neither is likely to be informative except under restrictive conditions that are unlikely to be satisfied in many contexts. To test empirical relevance, we also apply the approaches to a real-world setting where estimator performance is known. Both approaches are worse than random at selecting estimators which minimise absolute bias. They are better when selecting estimators that minimise mean squared error. However, using a simple bootstrap is at least as good and often better. For now researchers would be best advised to use a range of estimators and compare estimates for robustness. 1192

Theory of Mind and Strategic Decision-Making


Neha Bose and Daniel Sgroi

In a laboratory experiment, 338 participants were asked to communicate in pairs
and then play two games with their partners: the 11-20 money request game (a tool for assessing level-k reasoning) and a public goods game. The communication occurred prior to any knowledge of what was to follow but played an important role in allowing them to develop theories or mental models of their partners (“theory of mind”) which proved to be crucial explanatory factors for decision-making. We examine the players’ beliefs about the personality and intelligence of their partner, how they play in the games and analysed the language used during communication. The results indicate that beliefs about partner’s type is biased by own-type. In particular, extraverts, characterised by positive affect, projected their positivity onto their partners. The level-k strategy chosen in the 11-20 game increased with the perceived similarity between players and in the public goods game, players cooperated more when they believed their partners to be extraverted. An analysis of the text used during communication explains how it was possible for participants to draw inferences about other’s type: for instance, use of more words and more dominant words were associated with being an extravert.
1191

Interview of Peter J Hammond

Philippe Mongin
GREGHEC, Paris

Following an initiative of Social Choice and Welfare, this is the result of an interview conducted by email exchange during the period from July 2017 to February 2018, with minor adjustments later in 2018. Apart from some personal history, topics discussed include: (i) social choice, especially with interpersonal comparisons of utility; (ii) utilitarianism, including Harsanyi’s contributions; (iii) consequentialism in decision theory and in ethics; (iv) the independence axiom for decisions under risk; (v) welfare economics under uncertainty; (vi) incentive compatibility and strategy-proof mechanisms, especially in large economies; (vii) Pareto gains from trade, and from migration; (viii) cost–benefit analysis and welfare measurement; (ix) the possible future of normative economics. 1190

Community Origins of Industrial Entrepreneurship in Pre-Independence India

Bishnupriya Gupta, Dilip Mookherjee, Kaivan Munshi,
& Mario Sanclemente

We argue that community networks played an important role in the emergence of Indian entrepreneurship in the early stages of the cotton textile and jute textile industries in the late 19th and early 20th century respectively, overcoming the lack of market institutions and government support. From business registers, we construct a yearly panel dataset of entrepreneurs in these two industries. We find no evidence that entry is affected by prior trading experience or price shocks in the corresponding upstream sector. Firm directors exhibited a high degree of clustering of entrepreneurs by community. The dynamics of entry is consistent with a model of network-based dynamics 1189

Organizing Competition for the Market

Elisabetta Iossa, Patrick Rey, Michael Waterson

The paper studies competition for the market in a setting where incumbents (and, to a lesser extent, neighboring incumbents) benet from a cost advantage. The paper first compares the outcome of staggered and synchronous tenders, before drawing the implications for market design. We find that the timing of tenders should depend on the likelihood of monopolization. When monopolization is expected, synchronous tendering is preferable, as it strengthens the pressure that entrants exercise on the monopolist. When instead other firms remain active, staggered tenderingis preferable, asitmaximizes the competitive pressure that comes from the other firms. 1188

Rigidities and adjustments of daily prices to costs: Evidence from supermarket data


Monica Giulietti,
Jesus Otero,
Michael Waterson

We assess the extent of inertia in grocery retail prices using data on prices and costs from a large supermarket chain in Colombia. Relative to previous work our analysis benefits from the daily frequency of the data and the availability of reliable replacement cost data. We uncover evidence supporting the existence of significant nominal rigidities in reference prices (three months) and even more so in reference costs (about five months). There is evidence that the price and cost rigidities differ depending on the type of product, being on average smaller in the case of perishable goods. Using an Error Correction Model framework, we examine the path of prices relative to costs, to determine the speed of adjustment of prices to shocks. 1187

Historical Analysis of National Subjective Wellbeing using millions of Digitized Books

Thomas Hills, Eugenio Proto & Daniel Sgroi

We develop a new way to measure national subjective well-being across the very long run where traditional survey data on well-being is not available. Our method is based on quantitative analysis of digitized text from millions of books published over the past 200 years, long before the widespread availability of consistent survey data. The method uses psychological valence norms for thousands of words in different languages to compute the relative proportion of positive and negative language for four different nations (the USA, UK, Germany and Italy). We validate our measure against existing survey data from the 1970s onwards (when such data became available) showing that our measure is highly correlated with surveyed life satisfaction. We also validate our measure against historical trends in longevity and GDP (showing a positive relationship) and conflict (showing a negative relationship). Our measure allows a first look at changes in subjective well-being over the past two centuries, for instance highlighting the dramatic fall in well-being during the two World Wars and rise in relation to longevity. (Updated March 2019) 1186