We examine how the measurement of aggregate wealth affects our understanding of wealth distribution. We explain why choices over wealth aggregates can affect the measured level and composition of wealth concentration. Applying this to the UK, we find estimates of the top 1% wealth share vary by 2.1pp – between 14.4% and 16.5% – in 2016-18, depending on the choices we make regarding aggregates and the source of distributional information. Alternative definitions for aggregates lead to a reranking of who is at the top, replacing 40% of individuals in the top 1%, and changing the share of women and older individuals. We discuss conceptual and measurement issues with the National Accounts as a source of wealth aggregates, and argue that in many cases they are poorly aligned in both regards with the measure of personal wealth one would like to target, and in practice are less comparable internationally than they initially seem. In the UK, where the wealth survey has reasonably good coverage across the distribution, we therefore prefer survey aggregates.

An established literature has studied potential biases in the economics publication process based on traits of authors. We complement such work by studying whether the subject matter of study relates to publication outcomes. We do so in the context of race-related research: work that studies economic well-being across racial/ethnic groups. We investigate the implicit career incentives economists have to work on such topics by examining paths to publication for a corpus of 22,056 NBER working papers (WPs) posted from 1974 to 2015. We use an algorithm to classify whether a given WP studies race-related issues. We then construct paths to publication from WPs to data on published articles, and compare paths for race-related WPs to various counterfactual sets of WPs. We document that unconditionally, race-related NBER WPs are less likely to be published in any journal, in an economics journal, and more likely to publish in lower tier economics journals. Once we condition on observable characteristics including field and author affiliations, differences in paths to publication largely disappear, and such work is actually slightly more likely to publish in top-tier economics journals. Consistent with unconditional differences in paths to publication being salient to researchers, we find evidence of ex ante selection into WPs studying race-related issues in that they are of higher readability than other WPs. To understand the interplay with selection of researchers, we compare results to paths to publications for 10,306 CEPR WPs posted from 1984 to 2015. We conclude by discussing implications for economists' incentives to contribute to debates on race and ethnicity in the economy.

Issues of racial justice and economic inequalities between racial and ethnic groups have risen to the top of public debate. Economists’ ability to contribute to these debates is based on the body of race-related research. We study the volume and content of race-related research in economics. We base our analysis on a corpus of 225,000 economics publications from 1960 to 2020 to which we apply an algorithmic approach to classify race-related work. We present three new facts. First, since 1960 less than 2% of economics publications have been race-related. There is an uptick in such work in the mid 1990s. Among the top-5 journals this is driven by the American Economic Review, Quarterly Journal of Economics and the Journal of Political Economy. Econometrica and the Review of Economic Studies have each cumulatively published fewer than 15 race-related articles since 1960. Second, on content, while over 50% of race-related publications in the 1970s focused on Black individuals, by the 2010s this had fallen to 20%. There has been a steady decline in the share of race-related research on discrimination since the 1980s, with a rise in the share of studies on identity. Finally, we apply our algorithm to NBER and CEPR working papers posted over the last four decades, to study an earlier stage of the research process. We document a balkanization of race-related research into a few fields, and its continued absence from many others – a result that holds even within the subset of research examining issues of inequality or diversity. We discuss implications of our findings for economists’ ability to contribute to debates on race and ethnicity in the economy.

Using administrative data on the globally connected super-rich in the UK, we study the effect of a large tax reform on migration behaviour. Prior to 2017, offshore investment returns for `non-doms' – individuals tax-resident in the UK but with connections to other countries – were untaxed. People making use of that tax status are strongly concentrated at the top of the income distribution: 86% are in the UK top 1% and 29% in the top 0.1% once overseas investment income is taken into account. A reform in 2017 brought long-stayers, who had been in the UK for at least 15 of the last 20 years, into the standard tax system, reducing their effective net-of-average-tax rate by 18%. We find that emigration responses were modest: our central estimate is that the emigration rate increases by 0.26 percentage points for a 1% decline in the net-of-tax rate, and we can rule out increases larger than 0.4 percentage points. Dispelling fears that the targeted taxpayers were able to circumvent the tax hike, we find large average increases in income reported and tax paid in the UK of more than 150%.

Using administrative data on the universe of UK taxpayers, we leverage major top tax rate reforms in the UK and France to evaluate how much top earners respond to tax increases by migrating. We document four main facts. First, looking across foreigners we find a migration semi-elasticity with respect to the net-of-average-tax rate of -0.2, somewhat lower than has been found for specific groups studied previously. Second, migration responses are driven by those with the highest predicted baseline emigration probability, highlighting the importance of accounting for heterogeneity. Third, there is little migration response from natives. Finally, we estimate the long term impact of tax changes on the stock of migrants among UK top earners taking a structural approach, and find that even our modest migration elasticity implies substantial stock changes in the long run.

In this paper we show the importance of international ties amongst the UK’s global economic elite, by exploiting administrative data derived from tax records. We show how this data can be used to shed light on the kind of transnational dynamics which have long been hypothesised to be of major significance in the UK, but which have previously proved intractable to systematic study. Our work reveals the enduring and distinctive influence of long-term imperial forces, especially to the former ‘white settler’ ex-dominions which have been called the ‘anglosphere’. These are allied to more recent currents associated with European integration and the rise of Asian economic power. Here there are especially strong ties to the ‘old EU-6’ nations of France, Germany, Netherlands, Belgium, Luxembourg, and Italy. The incredible detail and universal coverage of our data means that we can study those at the very top with a level of granularity that would be impossible using traditional survey sources. We find compelling support for the public perception that non-doms are disproportionately highly affluent individuals who can be viewed as a part of a global elite. However, whilst there is some evidence for the stereotype of the global wealthy parking themselves in the UK, this underplays the significance of the working rich. Our analysis also reveals the remarkable concentration of non-doms in central areas of London.

Aggregate taxable capital gains in UK have tripled in past decade. Using confidential administrative data on the universe of UK taxpayers, we show that including gains changes the picture of UK inequality over the past two decades. These taxable gains are largely repackaged income, so their exclusion biases the picture of inequality. Including them changes who is at the top of the distribution, adding more business owners and older people. The share of income plus gains (both pre- and post-tax) going to the top 1% is 3pp higher than for income only, and this gap has been steadily rising.

Poor households regularly borrow and lend to smooth consumption, yet we see much less borrowing for investment. This cannot be explained by a lack of investment opportunities, nor by a lack of resources available for investment. This paper provides a novel explanation for this puzzle: informal risk sharing can crowd out investment. I extend the canonical model of limited commitment in risk-sharing networks to allow for lumpy investment. The key insight is that the cost of losing insurance is lower for a household that has invested, since it has an additional stream of income. This limits its ability to credibly promise future transfers, and so limits its ability to borrow from other households. The key prediction of the model is a non-linear relationship between total income and investment at the network level – namely there is a network level poverty trap. I test this prediction using a randomised control trial in Bangladesh, that provided capital transfers to the poorest households. The data covers 27,000 households from 1,400 villages, and contain information on risk-sharing networks, income and investment. I exploit variation in the number of program recipients in a network to identify the threshold level of capital provision needed at the network level for the program to move the network out of a poverty trap and generate further investment. I also verify additional predictions of the model and rule out alternative explanations. My results highlight how capital transfer programs can be made more cost-effective by targeting communities at the threshold of the aggregate poverty trap.

Relatively little is known about what determines whether a heterogenous population ends up in a cooperative or divisive situation. This paper proposes a theoretical model to understand what social structures arise in heterogeneous populations. Individuals face a trade-off between cultural and economic incentives: an individual prefers to maintain his cultural practices, but doing so can inhibit interaction and economic exchange with those who adopt different practices. We find that a small minority group will adopt majority cultural practices and integrate. In contrast, minority groups above a certain critical mass, may retain diverse practices and may also segregate from the majority. The size of this critical mass depends on the cultural distance between groups, the importance of culture in day to day life, and the costs of forming a social tie. We test these predictions using data on migrants to the United States in the era of mass migration, and find support for the existence of a critical mass of migrants above which social structure in heterogeneous populations changes discretely towards cultural distinction and segregation.

Using administrative data on the universe of UK taxpayers, we study the contribution of migrants to the rise in UK top incomes. We show migrants are over-represented at the top of the income distribution, with migrants twice as prevalent in the top 0.01% as anywhere in the bottom 97%. These high incomes are predominantly from labour, rather than capital, and migrants are concentrated in only a handful of industries, predominantly finance. Almost all (90%) of the observed growth in the UK top 1% income share over the past 20 years has accrued to migrants.

Using anonymized administrative data on the population of UK taxpayers, we show that—in line with high-profile anecdotes about the tax affairs of the rich—effective average tax rates (EATRs) decline at the top of the distribution of income and capital gains. We also document substantial variation in EATRs within remuneration level: a quarter of those in the top 1 per cent pay headline rates, while another quarter pay at least 9pp less than the headline rate. Most of this effect is driven by the composition of remuneration, with investment income having lower tax rates and capital gains having lower rates still. If all individuals with income above £100,000 paid the headline rates, this would raise tax revenue on income and gains by £23 billion on a static basis, an increase of 27 per cent in the tax paid by this group.

We discuss the measurement of top incomes and wealth in the UK, and options for reforming their taxation. First, we highlight the importance of capital gains and migration in understanding long-term trends in top income shares, and of survey under-coverage at the top in understanding top wealth shares. We next consider the scope for reforms to the taxation of capital to tackle these inequalities, whilst also improving the efficiency of taxation, emphasising the roles of Capital Gains Tax, Inheritance Tax and Wealth Taxes. Finally, we examine the question of who is taxed, including the tax treatment of highly mobile individuals and of trusts.

We study the effects of audits on long run compliance behaviour, using a random audit program covering more than 53,000 tax returns. We find that audits raise reported tax liabilities for five years after audit, effects are longer lasting for more stable sources of income, and only individuals found to have made errors respond to audit. 60-65% of revenue from audit comes from the change in reporting behaviour. Extending the standard model of rational tax evasion, we show these results are best explained by information revealed by audits constraining future misreporting. Together these imply that more resources should be devoted to audits, audit targeting should account for reporting responses, and audit threat letters miss a key benefit of audit

We compare two approaches to measuring UK top income shares—the share of income going to particular subgroups, such as the top 1%. We set out four criteria that an ideal top share series should satisfy: (i) comparability between numerator and denominator; (ii) comparability over time; (iii) international comparability; and (iv) practical sustainability. Our preferred approach meets three of these; by contrast the approach currently used to produce UK fiscal income series meets none of them. Changing to our preferred approach matters quantitatively: the share of income going to the top 1% is 2 percentage points higher, but rising more slowly, than under the alternative.

How does economics compare to other social sciences in its study of issues related to race and ethnicity? We assess this using a corpus of 500,000 academic publications in economics, political science, and sociology. Using an algorithmic approach to classify race-related publications, we document that economics lags far behind the other disciplines in the volume and share of race-related research, despite having higher absolute volumes of research output. Since 1960, there have been 13,000 race-related publications in sociology, 4,000 in political science, and 3,000 in economics. Since around 1970, the share of economics publications that are race-related has hovered just below 2% (although the share is higher in top-5 journals); in political science the share has been around 4% since the mid-1990s, while in sociology it has been above 6% since the 1960s and risen to over 12% in the last decade. Finally, using survey data collected from the Social Science Prediction Platform, we find economists tend to overestimate the amount of race-related research in all disciplines, but especially so in economics.

Policymakers tend to ‘treasure what is measured’ and overlook phenomena that are not. In an era of increased reliance on administrative data, existing policies also often determine what is measured in the first place. We analyse this two-way interaction between measurement and policy in the context of the investment incomes and capital gains that are missing from the UK’s official income statistics. We show that these ‘missing incomes’ change the picture of economic inequality over the past decade, revealing rising top income shares during the period of austerity. The underestimation of these forms of income in official statistics has diverted attention from tax policies that disproportionately benefit the wealthiest. We urge a renewed focus on how policy affects and is affected by measurement.

We use administrative tax data from audits of self-assessment tax returns to understand what types individuals are most likely to be non-compliant. Non-compliance is common, with one-third of taxpayers underpaying by some amount, although half of aggregate under-reporting is done by just 2% of taxpayers. Third party reporting reduces non-compliance, while working in a cash-prevalent industry increases it. However, compliance also varies significantly with individual characteristics: non-compliance is higher for men and younger people. These results matter for measuring inequality, for understanding taxpayer behaviour, and for targeting audit resources.

Capital gains are particularly complex to tax given their infrequency, the different ways in which they are generated, and worries about harming productivity. There are theoretical arguments in support of everything from zero rates to high rates of tax on capital. In this paper, I first discuss the impact of capital gains on inequality, which often motivates discussions about how gains should be taxed. I then set out the principles that determine how gains should be taxed, in particular how the tax rate should relate to income tax rates. I propose that capital gains tax rates be equalized with income tax rates, subject to provisions to allow gains to be ‘smoothed’ over time and to remove inflation from the tax base. I highlight key transitional issues in moving to such a tax structure. Finally, I discuss the specific lessons for Canada.

This paper introduces a special issue on a Wealth Tax, which draws together the latest thinking on wealth taxes with the aim of filling this gap. It draws heavily on international experience and evidence, applying these insights to the UK context. The papers build on work undertaken for the Wealth Tax Commission, which delivered its final report in December 2020. The contributors to this special issue include tax practitioners and academic lawyers as well as economists, reflecting our view that this range of expertise is essential to evaluating the practice, as well as principles, of a wealth tax. In this paper we touch upon some common themes arising across the papers. We also highlight some important remaining gaps in the evidence base on wealth taxes, particularly on the measurement of wealth and behavioural responses at the very top of the wealth distribution.

In this paper we model the revenue that could be raised from an annual and a one-off wealth tax of the design recommended by Advani, Chamberlain and Summers (2020). We examine the distributional effects of the tax, both in terms of wealth and other characteristics. We also estimate the share of taxpayers who would face liquidity constraints in meeting their tax liability. We find that an annual wealth tax charging 0.18% on wealth above £500,000 could generate £10 billion in revenue, before admin costs. Alternatively, a one-off tax charging 4.8% (effectively 0.96% per year, paid over a 5-year period) on wealth above the same threshold, would generate £250 billion in revenue. To put our revenue estimates into context, we present revenue estimates and costings for some commonly-proposed reforms to the existing set of taxes on capital.

In this paper, we review the existing empirical evidence on how individuals respond to the incentives created by a net wealth tax. Variation in the overall magnitude of behavioural responses is substantial: estimates of the elasticity of taxable wealth vary by a factor of 800. We explore three key reasons for this variation: tax design, context, and methodology. We then discuss what is known about the importance of individual margins of response and how these interact with policy choices. Finally, we use our analysis to systematically narrow down and reconcile the range of elasticity estimates. We argue that a well-designed wealth tax would reduce the tax base (of reported wealth) by 7-17% if levied at a tax rate of 1%.

Household wealth is profoundly important for living standards. We show that wealth inequality in the UK is high and has increased slightly over the past decade as financial asset prices increased in the wake of the financial crisis. But data deficiencies are a major barrier in understanding the true distribution, composition and size of household wealth. We find that the most comprehensive survey of household wealth in the UK does a good job of capturing the vast majority of the wealth distribution, but that nearly £800 billion of wealth held by the very wealthiest UK households is missing. We also find tentative evidence to suggest that survey measures of high-wealth families undervalue their assets – our central estimate of the true value of wealth held by households in the UK is 5% higher than the survey data suggests.

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.

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.

Current UK energy use policies, which primarily aim to reduce carbon emissions, provide abatement incentives which vary by user and fuel, creating inefficiency. Distributional concerns are often given as a justification for the lower carbon price faced by households, but there is little rationale for carbon prices associated with the use of gas to be lower than those for electricity. We consider reforms that raise carbon prices faced by households, and reduce the variation in carbon prices across gas and electricity use, improving the efficiency of emissions reduction. We show that the revenue raised from this can be recycled in a way that ameliorates some of the distributional concerns. Whilst such recycling is not able to protect all poorer households, existing policy also makes distributional trade-offs, but does this in an opaque and inefficient way.

In many contexts we may be interested in understanding whether direct connections between agents, such as declared friendships in a classroom or family links in a rural village, affect their outcomes. In this paper we review the literature studying econometric methods for the analysis of linear models of social effects, a class that includes the `linear-in-means' local average model, the local aggregate model, and models where network statistics affect outcomes. We provide an overview of the underlying theoretical models, before discussing conditions for identification using observational and experimental/quasi-experimental data.

In many contexts we may be interested in understanding whether direct connections between agents, such as declared friendships in a classroom or family links in a rural village, affect their outcomes. In this paper we review the literature studying econometric methods for the analyis of social networks. We begin by providing a common framework for models of social effects, a class that includes the ‘linear-in-means’ local average model, the local aggregate model, and models where network statistics affect outcomes. We discuss identification of these models using both observational and experimental/quasi-experimental data. We then discuss models of network formation, drawing on a range of literatures to cover purely predictive models, reduced form models, and structural models, including those with a strategic element. Finally we discuss how one might collect data on networks, and the measurement error issues caused by sampling of networks, as well as measurement error more broadly.