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The increasing importance of knowledge in economies has led to the knowledge-based economy. In fact, in this type of economy, the accumulation of science and knowledge from research and development has led to an increase in the rate of return on research and development projects and plays a significant role in creating wealth for a country. Accordingly, the main purpose of this paper is to evaluate the relationship between knowledge Economy Index (KEI) and Gross Domestic production (GDP) for Iran’s Economy over the past 20 years. Therefore, the relation between knowledge Economy Index and GDP growth in 1996 to 2017 in Iran’s economy through The Johansen test has been investigated. Results confirm a long-run relation between KEI and GDP growth during the studied period. Considering the significant contribution of knowledge-based economy to GDP growth, it seems it is necessary to pay attention to constructive variables of the s knowledge Economy and the production of knowledge-based products for Iran’s economy. Regarding this result, policymaking for promoting knowledge-based economy should be concerned.

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The long run economic growth is one of the main economic requirements of countries in order to attain comprehensive development and increase the social welfare. This research aims to examine the effect of output uncertainty on economic growth for Iran during 1965-2011. Output uncertainty, gross domestic product, inflation and population are variables under study. In this paper, first, output uncertainty is computed using a generalized auto-regressive conditional heteroscedasticity (GARCH) model and then the effect of output uncertainty on economic growth is estimated though co-integration test and vector auto-regression (VAR). The findings show that output uncertainty reduces the long run economic growth in Iran. This result is in accordance with Bernanke (1983) and Pindyck (1991) studies. They concluded that increase in output uncertainty leads to decrease in both investment and long run economic growth. The findings also indicate the negative and positive effects of inflation and population growth, respectively, on the long run economic growth in Iran.