About the project
Image by Raphael Whittle
Find out more about the Harms of Extreme Wealth project, and the thinking and methods that underpin the Extreme Wealth Line. Explore our Q&A and research papers, submit relevant evidence, or connect with the wider network.
The review collates and evaluates evidence for the political, environmental, economic and social harms that are associated with the increasing level and concentration of wealth we observe in many societies today. It is part of a broader research programme to develop a social indicator on extreme wealth which we call an Extreme Wealth Line .
We argue in our methodology paper that setting an Extreme Wealth Line - differentiating 'ordinary' wealth from 'extreme' wealth - should be informed by evidence on the relationship between different levels and concentrations of wealth, on the one hand, and different levels and types of harm on the other.
The Line should be set at a point where the harms become socially unacceptable. The evidence is an important input to that decision, but it will also require expert and public deliberation to reach a consensus.
The definition of 'harm' we use (see our conceptual paper) is sociological: harm to members of society caused by a pattern or structure. It does not imply that the harm is intentional or that any specific individual is responsible.
The harms of extreme wealth are mostly experienced by people other than the wealthy. In that sense they can be thought of as 'negative externalities', although unlike conventional negative externalities (for example, from smoking), the harms of extreme wealth may be present even if there is no transaction or consumption.
For the purposes of the review, we have applied a flexible and inclusive definition of extreme wealth, encompassing, for example, high net worth, top wealth shares and high wealth inequality. This is because a more precise definition of what constitutes 'extreme' wealth depends on the outcome of the review: a level or concentration of wealth at which the harms associated with it become socially unacceptable.
Wherever possible, we focus on wealth (stock of resources) rather than income (flow of resources), but in some sources these are conflated.
We have grouped the evidence under four broad dimensions of harm: political, environmental, economic and social. However these are neither mutually exclusive nor exhaustive dimensions.
We have searched for academic, peer-reviewed, evidence on the relationship between wealth and each of these types of harm. The evidence is inter-disciplinary, including contributions from economics, history, law, sociology, political science, psychology and social policy.
The review follows the principles of systematic reviewing (for example, transparency and reproducibility) but resources did not permit a full-scale systematic review.
Because the evidence is drawn from many different disciplines, it uses many different methods - for example, natural experiments, correlational studies, long-run historical and/or comparative analysis and case studies. We have therefore taken an approach of evidential pluralism. This means that we are including studies that provide evidence on the mechanisms (sometimes called 'pathways') connecting extreme wealth to a particular kind of harm, as well as studies that quantify the correlation or test causation.
The plurality of evidence makes it especially important to evaluate the strength of the evidence overall. We do this through making an assessment of the evidential certainty jointly provided by the studies in the review for a relationship between extreme wealth and a particular type of harm. We separately assess whether the evidence shows a strong or a weak relationship between extreme wealth and that type of harm. See 'How are the results of the review reported?' below.
We summarise this for each kind of harm reviewed in a 'report card' with the following fields:
| Mechanism: | Summarises evidence on how extreme wealth can produce the harm | |
|---|---|---|
| Threshold: | Summarises evidence on the level of wealth or wealth concentration at which the harm occurs, or intensifies. It highlights any evidence of inflection points ('tipping points') in the relationship. (In practice, we found very few studies that identify inflection points). | |
| Evidence assessment: | Certainty of evidence: | Provides our judgement on the validity and reliability of the evidence for the mechanism, and, where relevant, the threshold. |
| Evidence assessment: | Strength of relationship: | Provides our judgement on what the evidence shows about the strength of the relationship between extreme wealth and the harm in question. This is distinct from the evidential certainty: it is possible to have weak evidence of a strong relationship, or strong evidence of a weak relationship. |
| Contextual factors: | Summarises which institutional, policy or other contextual factors the evidence suggests are important in moderating the relationship between extreme wealth and harm. | |
| Evidence gaps: | Summarises key weaknesses and gaps in the evidence base. | |
| Examples of strong studies: | A more comprehensive narrative review, with references to underlying studies, is linked from each report card. |
Please see the Dimensions of harm and the Country case studies listed below or download a complete pdf here.
Dimensions of harm
Case studies
Please see the summary of Evidence gaps.
The review team was Irene Bucelli, Eleni Karagiannaki, Tania Burchardt and Michael Vaughan. Ingrid Robeyns was an advisor. Irene led on the political, environmental and social dimensions; Eleni led on the economic dimension and on the country case studies. Tania and Michael provided direction and support.
The review was funded by Patriotic Millionaires UK through grants from the Joseph Rowntree Foundation and from Partners for Change, as part of the Extreme Wealth Line Initiative, with in-kind support from LSE.