Procyclic behaviour is an observable phenomenon in the world economy. Specifically, it describes the correlation between the performance of a good or service and the state of the economy at large. It is an important concept for understanding how markets, policies and fiscal behaviour adapt to changes to the economy.

At its most basic level, procyclic occurs when rising economic activity triggers a corresponding rise in the performance of a particular asset. A good example of this is the housing market, where increased levels of economic activity can push up demand for housing, increasing housing prices. This increase in prices creates a procyclic relationship between economic activity and the housing market. Similarly, when economic activity slows, there tends to be a corresponding dip in the housing market.

The same type of procyclic behavior can also be observed in other economic indicators. Gross Domestic Product (GDP) is one of the most widely used indicators of economic performance, and it is typically procyclic. When the economy is flourishing, GDP increases, and when it slows, GDP decreases. Likewise, labour is another example of a procyclic economic indicator--when economic activity is strong, businesses hire more workers, and when economic activity slows, businesses reduce their workforce.

Finally, marginal cost is another indicator of procyclic behaviour. As economic activity rises, businesses are willing to pay higher costs for materials and labour, thus pushing up marginal cost. When economic activity slows, businesses cut back on their inputs, reducing the marginal cost of production.

It is important to note, however, that procyclic behaviour is not the same thing as economic growth. Procyclic behaviour is more of an indicator of the current state of the economy, and it does not necessarily predict future growth. However, it can give insight into where markets and policies should adjust in order to ensure economic stability.

Overall, procyclic behaviour is an important concept in understanding economic dynamics. Not only does it describe the correlation between certain economic indicators and the state of the economy, but it can also provide insight into how markets and policies should adjust to ensure economic stability.