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Implicit contract theory

Implicit contract theory is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Implicit contract theory rather than just read about it. In short: In economics, implicit contracts refer to voluntary and self-enforcing long term agreements made between two parties regarding the future exchange of goods or services. Implicit contracts theory was first developed to explain why there are quantity adjustments (layoffs) instead of price adjustments (falling wages) in the labor market during recessions.

Key takeaways

  • Implicit contract theory belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Implicit contract theory to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Implicit contract theory from memory before moving on to harder problems.

Reference excerpt

In economics, implicit contracts refer to voluntary and self-enforcing long term agreements made between two parties regarding the future exchange of goods or services. Implicit contracts theory was first developed to explain why there are quantity adjustments (layoffs) instead of price adjustments (falling wages) in the labor market during recessions. The origins of implicit-contract theory lie in the belief that observed movements in wages and employment cannot be adequately explained by a competitive spot labour-market in which wages are always equal to the marginal product of labour and the labour market is always in equilibrium. In the context of the labor market, an implicit contract is an employment agreement between an employer and an employee that specifies how much labor is supplied by the worker and how much wage is paid by the employer under different circumstances in the future. An implicit contract can be an explicitly written document or a tacit agreement (some people call the former an "explicit contract"). The contract is self-enforcing, meaning that neither of the two parties would be willing to breach the implicit contract in absence of any external enforcement since both parties would be worse off otherwise. The interpersonal negotiation and agreement in implicit contracts contrasts with the impersonal and nonnegotiable decision making in decentralized competitive markets. As Arthur Melvin Okun puts it: a contract market is like an "invisible handshake" rather than the invisible hand.

Implicit contracts in the labor market

Layoff puzzle In traditional economic theory, a worker takes their wage as given and decides how many hours they work. The firm also takes the wage as given and decides how much labor to buy. Then wage is determined in the market to ensure total labor supply equals total labor demand. If workers supply more labor than firms demand, then the wage level should fall so that workers will work fewer hours and firms would demand more labor. Hence, when firms reduce labor demand during a recession, we should expect to see a fall in wages as well. However, in reality, firms layoff redundant workers while keeping the wage unchanged for the rest of the workforce, and the wage compensation fluctuates considerably less than employment does in a typical business cycle. Therefore, the law of supply and demand is insufficient to explain patterns in wages and employment.

Implicit contracts as insurance In an effort to explain the layoff puzzle, models with implicit contracts were independently developed by Martin Baily, Donald Gordon, and Costas Azariadis in 1974 and 1975. In their models, the firm and its workers are not simply the buyer and sellers of labor service in a sequential spot market; Instead, the employer and workers engage in a long term relationship that enables risk sharing. The key insight (or assumption) is that the employers are risk neutral while the workers are risk averse. This difference in attitude towards risk enables both parties to benefit from a long term employment relationship. Under the implicit contract, a worker is able to reduce the fluctuation in their labor income and the employer is able to increase their average profit. Hence, both parties are better off than being in the spot market. Therefore, the implicit contract between a worker and an employer is like insurance used to hedge the risk in the spot labor market. Layoffs act as the insurance premium that workers pay for the stability in the insurance schedule in the long run.

Decline of the theory in labor economics Despite the popularity of implicit contract theory in the 1980s, applications of the implicit contracts theory in labor economics has been in decline since the 1990s. The theory has been replaced by search and matching theory to explain labor market imperfections.

Implicit contracts in capital market Capital market shares some of the "imperfections" of the labor market discussed above: long term relationships between banks and borrowers act like the long term employment relationship between an employer and their workers. Like layoffs in the labor market, there is credit rationing in the financial market. Also, a typical loan contract is just like an employment contract illustrated in the model above: the loan repayment is fixed in all states of nature as long as the borrower is solvent. Hence naturally, economists tried to extend and apply the implicit contract theory to explain these phenomena in the capital market. The earliest studies to employ implicit contracts models in capital markets see the existence of credit rationing as part of an equilibrium risk-sharing arrangement between a bank and its customer: the bank is risk neutral, and the borrower is risk averse, hence they gain from a long term relationship via shifting the interest rate risk from the borrower to the bank. If loans are negotiated in the spot market, then the borrower would be exposed to fluctuations in the spot market interest rates on her loan. Instead, if the borrower engages in an implicit contract with a bank, the bank can shield the borrower from fluctuations in the spot market by offering her a constant rate on the loan and in return for a higher average interest rate in the long run. However, if every bank charges a higher interest rate than the average rate in the spot market, then there would be credit rationing. This approach hinges on the assumption that agents (bank and the borrower) have different attitudes towards risk. However, more recent studies of capital markets do not rely on different attitudes towards risk, instead they focus on asymmetric information and the default risk in the capital markets. Also, implicit contracts have been playing an important role in explaining credit rationing under asymmetric information.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Implicit contract theory

Start with the simplest possible case. Write down what Implicit contract theory claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Implicit contract theory before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Implicit contract theory ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Implicit contract theory

In research
Implicit contract theory appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Implicit contract theory in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Implicit contract theory is common in secondary-school and first-year university syllabi. It links to neighbouring topics Financial markets, Labour economics, New Keynesian economics, so understanding it makes those chapters shorter.
In everyday life
Look for Implicit contract theory outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Implicit contract theory in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Implicit contract theory means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Implicit contract theory out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Implicit contract theory in simple terms?

In economics, implicit contracts refer to voluntary and self-enforcing long term agreements made between two parties regarding the future exchange of goods or services. Implicit contracts theory was first developed to explain why there are quantity adjustments (layoffs) instead of price adjustments…

Why does Implicit contract theory matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Implicit contract theory?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Implicit contract theory.

Tags

  • Financial markets
  • Labour economics
  • New Keynesian economics

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