Economics

Exogenous Growth Model

Published Mar 22, 2024

Definition of Exogenous Growth Model

An exogenous growth model, also known as a neoclassical growth model, is a framework used in economics to explain long-term economic growth through external factors outside the control of an economy. These factors might include technological progress and innovation, which are considered to be independent of the economic activities within the model. The model focuses on how these external influences affect the accumulation of capital, labor productivity, and, consequently, the output of an economy.

Key Components

The exogenous growth model primarily consists of three components: savings, capital accumulation, and production function. Savings provide the funds necessary for investment in physical capital (machinery, buildings, etc.), which in turn accumulates to increase production capacity. The production function relates the input of labor and capital to the output of goods and services, offering insights into an economy’s productivity levels.

Technological Progress as an Exogenous Factor

In this model, technological progress is considered an exogenous factor, meaning it is assumed to improve over time independent of the economy’s current capital stock or labor force. This improvement leads to higher productivity, allowing for economic growth without necessitating proportional increases in input quantities. The exogenous growth model, therefore, attributes long-term growth to innovation and technology advancements introduced from outside the economic system.

Limitations of the Model

The main criticism of the exogenous growth model is its assumption that technological progress is an external force that affects all economies equally, regardless of their policies, investments in research and development, or educational standards. Critics argue that technological advancement is often the result of endogenous factors, such as a country’s investment in innovation, which are not adequately addressed by the model.

Example

Consider the case of two countries, A and B, with similar economic structures but differing policies on research and development (R&D). According to the exogenous growth model, if both countries experience the same rate of technological progress, they would see similar growth rates. However, in reality, Country A, which invests heavily in R&D, might experience faster technological advancements and, thus, higher growth rates than Country B, challenging the model’s assumption of technology as an entirely exogenous factor.

Why Exogenous Growth Model Matters

Despite its limitations, the exogenous growth model provides valuable insights into the fundamental drivers of economic growth and the role of technology in enhancing productivity. It helps policymakers and economists understand the potential impact of external technological innovations on an economy. Additionally, it offers a baseline from which to explore the effects of different savings rates, population growth, and other factors on economic outcomes.

Frequently Asked Questions (FAQ)

How does the exogenous growth model differ from endogenous growth models?

The exogenous growth model attributes economic growth to factors external to the economy, particularly technological progress. In contrast, endogenous growth models assert that economic growth is primarily driven by internal factors such as human capital, innovation, and knowledge, which are influenced by the economic policies and decisions within the economy.

Can the exogenous growth model be applied to developing countries?

Yes, the exogenous growth model can be applied to developing countries to analyze the impact of external factors like foreign technology transfer on economic growth. However, its applicability might be limited due to the model’s assumptions, such as the uniform impact of technology across countries, which might not hold true in the diverse economic environments of developing nations.

What role does government policy play in the exogenous growth model?

In the exogenous growth model, government policy plays a secondary role, mainly influencing the investment rate through savings and the efficiency of capital accumulation. However, the model itself assumes that long-term economic growth is driven by external technological progress, which is not directly controlled by government policies. This is a marked difference from endogenous growth models, where policies directly affecting innovation and education can significantly influence growth outcomes.

Is there a real-world example where the exogenous growth model has been observed?

The post-World War II economic expansion experienced by the United States and other developed countries can be partially explained by the exogenous growth model, where rapid technological advancements, including the widespread adoption of computers and the internet, significantly boosted productivity and economic growth, independent of the immediate economic actions of these countries.
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