Buying Power: an often neglected, yet essential concept for economics

Buying power is a concept that is absent from basic economic theory, and this has major implications both for theory and for the practical issues that we face. This absence is odd because buying power is central to how the economy works. Its importance is not a new observation.  

By Michael Joffe.

In 1776, Adam Smith wrote that the degree to which a “man is rich or poor” depends mainly on the quantity of other people’s “labour which he can command, or which he can afford to purchase” (emphasis added). However, this idea of differential buying power has never been incorporated into economic theory, despite it being an obvious feature of the world we live in. The extent of a person’s disposable income and wealth gives them a corresponding degree of influence. It is like a voting system, where everybody votes for their view of what the economy should produce, but where the number of votes is very unequal. The term “power” here is best understood as meaning the degree of ability of a person or organization to bring something about. It is a causal (not e.g. a moral or political) concept.

Examples of its importance are everywhere. When prices rise, some potential consumers may be excluded – a form of rationing. In pleasant locations, affluent urban dwellers buy holiday homes, crowding out the local inhabitants who do not have the buying power to compete and therefore may have to leave the area. In low-income countries, the amount of transactional sex depends on inequality (the buying power of richer men), not poverty. Any industry depends on its (potential) customers’ buying power for support: washing machine manufacture is only possible if there is a market of people who can afford their product; luxury goods such as mega-yachts exist because there are mega-rich people to buy them.

Firms also have buying power, in varying degree, which enables them to transform the world, e.g. by taking possession of land and natural resources. Within the firm, the employers’ buying power is what enables them to employ workers, thereby creating the authority structure. And shareholders’ influence over the conduct of firms’ directors results from their ability to have bought shares. Finally, when China’s economy was expanding rapidly, its buying power created a worldwide commodities boom, with major impacts on (for example) Australia and Brazil, an impact that has diminished in recent years.

With a concept that is so obvious, one might expect it to be a prominent feature of economic theory. But in fact, it is only patchily represented. Notably, basic consumer theory obscures it completely, by looking at a potential consumer’s decision making given the amount of money that they have to spend – the fixed “budget constraint”. This naturally leads to a conception of the economy that neglects the role of effective demand.

At the aggregate level, in macroeconomics, buying power is represented: it is Keynes’ key concept of aggregate demand. It is also implicit in the flow diagrams that are often used to introduce students to economics, showing two-way flows with money in one direction and goods/services in the other, e.g. between households and firms in the aggregate.

Much of the controversy in economics is concerned with disputes over the competing varieties of macroeconomic theory, and other topics that are directly policy related. Commentators often say that micro is in a satisfactory condition, e.g. on the grounds that it is largely evidence-driven in specific areas such as labor economics, healthcare, education, etc. It is true that some good work is done in these applied areas. But the implication is that macro is the only problem, and this lets mainstream micro theory off the hook.

One implication – which is replicated across sub-disciplines such as health economics – is that the focus is mainly on the willingness to pay, obscuring the importance of the ability to pay. More broadly, it means that economics is a form of decision theory, and this often produces a default way of thinking that treats inequalities as an afterthought, rather than being inherent in how the economy operates. It has taken a huge rise in inequality in countries like the US and the UK, plus Piketty’s best-selling book, to bring this issue to mainstream attention.

This is especially problematic in the context of the widespread orthodox view that macro theory should be based on “micro-foundations” as if the micro theory is totally unproblematic. It implies adopting the extreme version of rationality assumed by mainstream microeconomic theorists, as well as optimization and so on. Naturally, there must be some correspondence between theories at the micro and macro levels – but that needs to involve concepts that correspond to the real world, both at the micro and macro levels.

But there is more: buying power is not the only type of economic power that we fail to recognize. Whilst monopoly power features in textbook economics and bargaining power is recognized, e.g. in game theory, other important types are neglected. These include corporate power and the power of the financial sector including the power of banks to create money. They overlap to some extent with buying power, but also have additional features that are beyond the scope of this article. This analysis is part of a broader rethinking of the foundations of economics, using concepts that actually correspond to the way the economy works – evidence-based economics.

Vast disparities in buying power have major macroeconomic and societal results. Inequality tends to lead to private-sector debt, which creates a vicious cycle, further enhancing the inequality. Private-sector debt also generates systemic instability and a risk of financial crisis. An IMF study concluded that restoring the bargaining power of the lower income groups would be the best way of reducing this debt, and enhancing the stability of the system.

Another consequence is environmental: increasingly rich consumers, in satisfying their wants, inflate their ecological footprints and damage the carrying capacity of the Earth. Recognizing and addressing over-consumption can play a major part in reducing our environmental impact.

Thus, buying power plays a central role, both in how the economy works and in pressing practical issues, and it is a serious error to ignore it. By incorporating it into our core thinking, we will be much better equipped to understand the economy and to address the challenges of increasing inequality, systemic instability, and environmental degradation.

About the Author
Michael Joffe was originally trained as a biologist, and for many years carried out epidemiological research at Imperial College, where he is still attached. He now applies his insight into the way that the natural sciences generate secure causal knowledge to his work in economics.

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