Payame Noor University Economic Growth and Development Research 2228-5954 8 32 2018 09 23 Determining the Optimal Threshold Government Size and its Productivity Application of the Threshold Panel Data Approach in Selected OPEC Countries Determining the Optimal Threshold Government Size and its Productivity Application of the Threshold Panel Data Approach in Selected OPEC Countries 124 111 4544 10.30473/egdr.2018.4544 FA Mohammad Sokhanvar Assistant Professor of Economics, Urmia Branch, Islamic Azad University, Urmia, Iran Journal Article 2017 10 11 In this paper, government expenditure productivity has been studied in selected countries that are member in Organization of Petroleum Exporting Countries (OPEC) and optimum threshold government size of these countries is determined. For this reason, endogenous Barrow growth model is used that practically applied by Karras. Panel data threshold approach is applied. The reason for selecting these countries for study is that these countries have the same government financial structure such that a high share of budget of these countries depend on the oil revenue. According to available data, eight countries are selected and the period under study is from 2000 to 2014. Estimation findings show that optimum threshold government size of these countries have been estimated 13/58. In addition, findings indicate that before the threshold government size, the productivity of government size has been positive and approximately 0/72 and after the threshold government size, the productivity of government size has been negative and approximately    -0/23. In this paper, government expenditure productivity has been studied in selected countries that are member in Organization of Petroleum Exporting Countries (OPEC) and optimum threshold government size of these countries is determined. For this reason, endogenous Barrow growth model is used that practically applied by Karras. Panel data threshold approach is applied. The reason for selecting these countries for study is that these countries have the same government financial structure such that a high share of budget of these countries depend on the oil revenue. According to available data, eight countries are selected and the period under study is from 2000 to 2014. Estimation findings show that optimum threshold government size of these countries have been estimated 13/58. In addition, findings indicate that before the threshold government size, the productivity of government size has been positive and approximately 0/72 and after the threshold government size, the productivity of government size has been negative and approximately    -0/23. https://egdr.journals.pnu.ac.ir/article_4544_d80dad68ced3d75bfde11b7c33a724f1.pdf