On the Capital/Output Ratio

A post on the capital output ratio was perhaps inevitable given my teaching and research engagements with macroeconomics, growth theory, and capital theory. This blog post seeks to critically discuss some of the manifestations of the capital-output ratio (K/Y ratio henceforth) in economics. 

K/Y ratio in Macroeconomics

The K/Y ratio captures a technological characteristic of the economy as a whole. It conveys to us the amount of capital required to produce one unit of output. A reduction in it therefore implies we require less capital to produce one unit of output. 

Since capital refers to the stock of produced means of production, which are of a heterogenous nature, K for the economy as a whole requires aggregation via prices: k1p1+k2p2+…+knpn=K. That is, K refers to, as H. G. Jones puts it (p. 17) in his 1975 book An Introduction to Modern Theories of Growth, “an index of aggregate capital.” Of course, Y too requires aggregation via prices.

Roy Harrod, in the chapter ‘Capital Output Ratio’ in Economic Dynamics (1973) treats K/Y ratio as a “kindred concept of the capital-labour ratio” (p. 46). Subsequently, he outlines the scope of the capital-labour ratio in economic studies. 

“It is to be stressed that the capital-labour ratio is a useful weapon for comparing alternative methods of producing a given object, for comparing methods of producing different objects or for comparing the changes through time of methods of producing a given object. It is on the whole an unserviceable tool in relation to national income as a whole, but it can be employed in a very rough sort of way for comparing different countries” (p. 48, emphasis added). 

Similarly, Harrod writes that “the concept of the capital labour ratio is not very helpful, if applied to the economy as a whole, owing to the difficulty of assessing the value of K, namely capital as a whole” (p. 50). 

Additionally, I think that such an aggregate conceptualization conceals more than it reveals. For instance, it conceals the nature of interdependence of production in an economy. What if K/Y changes because of a change in the nature of structural interdependence? Or, what if it changes because of a change in the volume and composition of aggregate consumption demand? After all, the volume of investment influenced by consumption. As Keynes rightly writes in Chapter 8 of The General Theory, “capital is not a self-subsistent entity existing apart from consumption”. 

K/Y ratio in Growth Theories

The K/Y ratio is used as an argument in Kaldor’s (1957) stylized facts: ‘steady capital-output ratios over long periods’. Here too, what is it saying about the structural nature of production and consumption in the economy? 

While Kaldor is talking about ex-post K/Y ratios, the ex-ante K/Y ratio plays a crucial role in Harrod’s growth equation g=s/v. Here, s refers to the marginal propensity to save and v refers to the desired or normal K/Y ratio. A decrease in v raises g, or more accurately, the ‘warranted rate of growth’. 

In the super abstract setup of the corn model (as in Ricardo) or the single-commodity model (as in Solow), since the input and the output are the same commodity, aggregate K is a homogenous set. This assumption allows us to sidestep the problems associated with the measurement and aggregation of ex-ante K. 

One cannot help but wonder how Solow’s single-commodity growth model (expressed via the aggregate production function) continues to be applied in growth accounting exercises on actual multi-commodity economies. We had noted some of the theoretical and empirical problems with one such exercise on the Indian economy in a short note in Economic & Political Weekly.  

K/Y ratio and Capital Theories

Capital theories are concerned with the conceptualization, measurement, valuation, determination, and aggregation of capital. Owing to the central role capital plays in production, the choice of the capital theory has a significant impact on both microeconomics and macroeconomics. Moreover, since capital accumulation is central to growth theory, the choice of the capital theory has a significant impact on development theories too. Similarly, on international trade theories; on this subject, you can consult the 1979 book Fundamental Issues in Trade Theory edited by Ian Steedman. 

In sum, while mathematization of the growth models gives us a better sense of its grammar, capital theory helps us understand its epistemology. And it is the latter which can better guide the use of K/Y ratio in economic theories, empirics, and policies.  

Who prices the products’

Recently, Indians have witnessed an escalation in onion prices followed by a hike in fuel prices. Price rise is a phenomenon which affects all sections of the society in varying degrees. Earlier, through the work of Michal Kalecki, a Russian economist, this blog showed the difference between cost-determined and demand-determined prices. The current post examines how products are priced. Majority of the arguments in this post is taken from the book Smart Pricing, authored by Jagmohan Raju and Z. John Zhang published in 2010.

Textbook economics teaches us that it is demand and supply which determine prices. Are the prices of vegetables, rice, chicken, train travel, milk, bread, toothpaste, parathas, etc determined in a similar way’ When price changes are attributed to demand and supply, it means that prices are taking their ‘normal course’. In other words, price movements arising from demand and supply are considered as normal as the law of gravitation. Economic theory ascribes the term ‘invisible hand’ to denote demand and supply factors which cause prices to alter. However, as repeatedly pointed out in this blog, manufactured goods and producer/consumer services are not priced in the market via bargaining. As Raju and Zhang rightly point out, ‘Price setting is a tangible process with a tangible outcome ‘ a dollar figure. The process of arriving at that number might not be tidy, but it cannot be so mysterious that it does not involve any human intervention. Someone, somewhere must make a concrete, numerical decision about the price of a product or service’ (2010, p 2). Further, they argue that ‘the market does not set prices. Marketers do. All the prices we observe in the marketplace do not just spring out of an autonomous, impersonal market. The managers’ hands in setting those prices are entirely ‘visible,’ regardless of whether such interventions are acts of expediency or strategy’ (Ibid, p 11-12).

According to Raju and Zhang products are usually priced based on three approaches: (1) cost-plus based, (2) competition based and (3) consumer based. An overwhelming majority of U.S. Companies use this approach to set prices. Here, the mark-up is determined by the company’s targeted internal rate of return on investment or by some vaguely defined industry convention. Competition based pricing is the second most popular approach and is considered to be strategic. In this approach, the prices are fixed taking into account the prices of similar products in the market. In the case of consumer based pricing, the company tries to determine how much each consumer is willing to pay and then accordingly fixes a price. All the above mentioned approaches indicate that price fixing is a conscious and deliberate action carried out by the company or individual producer.

In microeconomics textbooks and in the media we find statements which ascribe price rise to demand-supply factors. The group of individuals ‘ the capitalists, the brokers, the intermediaries etc ‘ who cause the prices to rise with their actions are completely absent in this account. The book by Raju and Zhang therefore is a must read for all economists who wish to understand how products are actually priced in today’s consumerist society.


Raju, Jagmohan and Zhang, John (2010), Smart Pricing: How Google, Priceline, and Leading Businesses Use Pricing Innovation for Profitability, Pearson Education: New Jersey.

On Prices

This is a part of a series which aim at elucidating the notion of ‘prices’ in various periods in history and according to various economists (mainly heterodox). What do prices convey’ How are prices formed’ Is there any mechanism underlying the formation of prices or is it random in nature’ Is there a possibility of finding ‘natural laws’ which determine prices’

In reality, we often come across various kinds of prices ‘ wholesale price, retail price, administered price, maximum retail price (mrp), etc. In economics, neoclassical theories posit that prices are determined owing to the interaction or intersection of supply and demand. What prices are they talking about’ These are prices which are abstract in nature. Theorising is done for practical purposes; therefore, theoretical entities are constructed in order to understand the ‘real’ world. Does the demand-supply theory enlighten us’ Does it provide an approximation of price formation in reality’ Or does it only tell us about a special set of commodities’ In the secondary market which carries trading in shares, prices are formed according to the demand and supply. But, would it be right to say that prices of automobiles, mobile phones, eatables, etc are fixed by the same mechanism’ Wouldn’t it be the producer who fixes theprice taking into account the cost of producing and transporting it, over which she/he charges a percentage as profit’

Keeping these questions in mind, let us move on to the issues pertaining to ‘prices’ in period between 12th and 16th centuries. The period is roughly before the period known as the mercantile period. The establishing of a ‘just price’ was a significant issue then. Actually, this debate goes back even to the time of Aristotle. Prices then has more to do with ethics and morality than with objective mechanisms of equilibrium or competitive conditions. Now, it is clearly seen how ‘economic theory’ rationalities a lot of price hikes by providing the reason that ‘demand is more than supply’. I ask the question which prevailed in early centuries: is such a price rise just’ How does one say that it is rational for prices to increase when there in excess demand’ Where does the rationale come from’ Economic theory! Who constructs these theories’ And what are the implications’ Who does it benefit’

In the earlier centuries, trading or exchange was carried out only by a few people. People exchanged after their needs were met. According to Thomas Aquinas, just price was the price that prevailed in the markets in the absence of fraud or monopolistic practices. This conception is reminiscent of the underlying power structure which prevailed at time. ‘Just’ did not necessarily mean just. And, this period was characterised by a lot of political interventions (especially, in Italy). Some other writers considered as ‘just’ that price which allowed producers to maintain a standard of living befitting their position in society. That is, the cost structure was determined by social stratification.

In the debates on ‘price’, references to utility and rarity was abundant. Another price ‘ the legitimate price also prevailed. It referred to the price which was fixed in any transaction agreed on by the participants freely. Again, the ‘freedom’ here is questionable. For, liberal authors argue that the transaction carried out by a CEO and a wage labourer is ‘just’ because both of them are freely participating. Surprisingly, the origin of property rights is seldom mentioned.

To conclude, this is a post inspired by the sub-disciplines of economic history and history of economic thought, which is rapidly vanishing from the departments of economics.


1) Roncaglia, A (2005), The Wealth of Ideas: A History of Economic Thought, CUP.