The Tax Research glossary seeks to explain the terms used on this blog that refer to more technical aspects of economics, accounting and tax. It recognises that understanding these terms is critical to understanding the economic issues that affect us all the time.

Like the rest of the Tax Research blog, this glossary is written by Richard Murphy unless there is a note to the contrary. It is normative approach and reflects post-Keynesian, heterodox economic opinion with a bias towards modern monetary theory. The fact that many items in that sentence are hyperlinked shows that they are explained in the glossary.

The copyright notices pertaining to the Tax Research blog apply to this glossary.

The glossary is designed to achieve three goals:

  • It seeks to provide a short, hopefully straightforward, definition of what a term might mean.
  • It then seeks, when appropriate, to explain what the term means within the context in which it is used. This is meant to elaborate the definition to add to understanding.
  • It then critiques the term, explaining, if appropriate, what the weaknesses inherent in the term or the situation it describes are. The aim here is to empower the reader to understand the issues behind the nonsense that most professions create around their activity to provide them with a mystique that they rarely deserve and which often hides what they are really up to.

The glossary is not complete. It will grow over time. If you think there are entries that need adding please let me know by emailing Please also feel free to suggest edits. The best way to do this is to copy an entry into Word and then send me a track-changed document indicating the changes that you suggest.

Because of the way in which it is coded this glossary automatically cross refers entries within itself and to the blog that it supports and within the glossary itself but if you think a link is missing please let me know.

Finally, if you like this glossary then you might like to buy me a coffee. It has required the support of a fair few to write it. You can do so here.

Glossary Entries

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Economically active population

The economically active population of a place comprises "all persons of either sex above a specified age who furnish the supply of labour for the production of economic goods and services (employed and unemployed, including those seeking work for the first time)  during a specified time reference period." (OECD).

The proportion of the population that is economically active can be a useful indicator of the health of an economy and its capacity for growth. The ratio can, however, change between jurisdictions because of differing social norms.

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Equilibrium is the state to which classical,  neoclassical and neoliberal economists all think that an economy should aspire.

Equilibrium exists at the point where supply and demand within an economy are matched and no participant in that economy has an incentive to change their position because to do so would leave them worse off, meaning that the optimal situation that equilibrium suggests exists will have been foregone.

Theories of equilibrium assume that all participants in an economy are:

  • Rational, meaning that they behave consistently.
  • Are in possession of perfect knowledge i.e. they not only know what they want to achieve at a point in time and how they might achieve it because they are aware of all the options available to them but are also aware of this information for all time to come.
  • Aware that equilibrium is the outcome of a dynamic process that they now wish to halt because an optimal outcome has been reached not only for themselves but all other market participants.

The idea of equilibrium, with the stable state that it implies, is borrowed from physics, where it can be observed. In contrast, economic equilibrium has never been achieved because the conditions for it to do so are quite obviously absurd and contradict all known and observable human behaviour.

Because it is claimed that supply and demand are stable and have delivered both optimal prices and optimal levels of supply at the point at which economic equilibrium happens the theory of equilibrium is necessarily dependent upon and embraces theories of market supply and demand and of the profit maximising firm upon which the foundations of neoclassical economics (are built, as are those of neoliberal economics. These theories are built upon the idea that a firm can accurately predict the demand for its product at each price at which it might offer it for sale and also its own marginal (or total additional) cost of producing each item that it supplies at every possible level of production so that it can equate its supposed marginal cost for an item it makes available for sale with the additional or marginal extra revenue that it will generate from doing so. It is then argued that the firm in question will continue to supply that product until such time as the two are equal.

It is important to note that no firm in history has ever been in possession of this information.

It is also important to note that the only conditions in which they might have this information are those where:

  • The products of one firm are incapable of being differentiated from those of another firm so that the consumer is indifferent as to which firm supplies them, which is almost certainly a condition that has never existed.
  • There are many firms in a market and each is so small that they cannot influence the price of the product that they make in that market, which is an assumption that contradicts what is now known about the behaviour of even very small numbers in mathematics.
  • There are no barriers to entry to firms that wish to make supplies in a market meaning that it is assumed that all firms can have access to the technology, labour and capital that they need to have possession of to make a product. It is also assumed that each firm who wants it can also have such possession instantaneously if a change in demand for the product requires that additional supply be created it can be delivered instantaneously. These conditions have never existed anywhere, at any time.

The implication of these conditions is that only markets can deliver equilibrium outcomes within economies and what is assumed to be the distortionary activity of government is not required because the optimal position created by a market meeting these conditions cannot be bettered.

Although, as noted, it is impossible that the conditions that might deliver economic equilibrium might ever exist the achievement of this state remains the goal for almost all neoclassical economics and neoliberal economics. The argument that each presents that government interference prevents equilibrium is not based on an analysis of any achieved state of equilibrium but solely upon the assumption that government action will prevent this state being achieved when that is already inevitable because equilibrium will always, as a matter of fact, be impossible to deliver.

It is accepted that neoclassical and neoliberal economists can and do relax the assumptions pertaining to the achievement of equilibrium when undertaking their work, and this cannot be disputed. However, this relaxation is usually undertaken to determine the supposed cost of the sub-optimal outcome that they suggest arises within the economy as a consequence of that sub-optimal behaviour so that they might suggest the gain that might arise if only the perfect market to which they (alone) aspire was in operation. As such these relaxations are largely meaningless.

The concept of equilibrium lies at the very heart of neoclassical, neoliberal and positive economics and so at the very heart of much of the work of the economics profession whilst simultaneously explaining why most of the work of that discipline is as inevitably flawed and destined to fail as that of the alchemists always was. If you work on the basis of flawed assumptions you can never achieve a useful result.



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EU Code of Conduct on Business Taxation

The EU Code of Conduct on Business Taxation promotes fair tax competition both within the EU and beyond.

The original Code of Conduct was agreed by EU finance ministers in 1997 as an intergovernmental, legally non-binding instrument. It has been primarily used to identify and assess preferential tax measures (i.e. measures that provide for a lower level of taxation than the level which is applicable in general) that are possibly harmful.

On 2022 the Ecofin Council approved a revised Code of Conduct, broadening the scope to include not just preferential tax measures but also 'tax features of general application', which create opportunities for double non-taxation or can lead to the double or multiple use of tax benefits.

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Exchange traded funds

Exchange traded funds (ETFs) are collective or pooled investment funds that are quoted on stock exchanges.

The funds usually have a very narrow focus. They do, for example, invest in government bonds, or a particular stock exchange or commodity index. They might also have a particular sector focus.

Exchange traded funds provide a compromise between collectivising risk and targetted investing.

The big concern with ETFs is with regard to their liquidity in the event of rapid changes in the perception of the value of either the fund or the underlying sector in which they invest.

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Excise duties

Excise duties are specific sales taxes usually added to the price of goods that are considered harmful or which create a specific economic externality.

Excise duties are commonly applied to tobacco, alcohol and carbon-based products but can be used for other purposes.

Excise duties are very effective revenue-raising taxes, partly because of the price inelasticity of demand for many of the products to which they are applied, e.g. cigarettes, which are consumed by those addicted to nicotine whatever the price charged.

The revenue raised is often dependent upon the ability of a jurisdiction to control smuggling and illicit products. Excise duties have a social as well as a revenue function (see entries on the reasons to tax).

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Export Processing Zones

Export processing zones are artificial enclaves within states where the usual rules relating to taxation and regulation are suspended to create what are, in effect, tax havens within larger countries.

The rules that are relaxed may be for import and export taxes or corporation taxes or all three and may also extend to relaxing other regulations e.g. on health and safety or the environment. There may also be a relaxation of local taxes e.g. land taxes and social security charges.

See also freeports, of which these zones are a type.

As with all freeports, these zones are open to abuse, fraud and criminality, because of the relaxed regulation that tends to typify their operation. There is little evidence that they add economic value to the locations that host them.

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Externalities are the costs that a product gives rise to which are not usually reflected in its sale price because they are borne by society at large and not by the specific consumer of the item made available for sake e.g., the pollution from driving a car is an externality the cost of which the motorist does not directly bear.

Excise duties are often used to correct for the cost of externalities.

Tax externalities can arise from the impact one tax or the practice associated with one tax base can have on other taxes or tax bases, both within and between countries. These externalities are also known as tax spillovers.

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