كليدواژه :
جانشيني بين نهاده ها , حالت , مسير توسعه , مدل فضا , مقياس توليد
چكيده فارسي :
بازدهی نسبت به مقیاس و كشش جانشینی عوامل تولید در زمره عواملی هستند كه نقش تعیین‌كننده‌ای در تقویت و یا تضعیف میزان اثرگذاری اعتبارات سرمایه‌گذاری در ایجاد اشتغال دارند. در این تحقیق با استفاده از داده های سال های 1353 تا 1391 تأثیر كشش جانشینی و بازدهی به مقیاس بر میزان اثرگذاری سرمایه‌گذاری در ایجاد اشتغال در بخش كشاورزی با استفاده از روش های حداقل مربعات معمولی، حداقل مربعات استوار و مدل‌های خطی تعمیم‌یافته برآورد گشته و مورد آزمون قرار گرفته است. یافته‌ها مؤید تأثیر مثبت بازدهی نسبت به مقیاس و تأثیر منفی كشش جانشینی عوامل تولید بر ضریب اثرگذاری سرمایه‌گذاری بر اشتغال بخش كشاورزی است. بنابراین تخصیص اعتبارات به زیر بخش های دارای بازدهی به مقیاس بالاتر و یا اجرای برنامه های تقویت كننده بازدهی به مقیاس و بهره وری از جمله جلوگیری از خرد شدن زمین های كشاورزی و استفاده از سیستم های نوین آبیاری، در كنار اعطای تسهیلات می تواند اثربخشی ابزار تسهیلات را در ایجاد اشتغال بهبود بخشد. همچنین تخصیص بیشتر منابع سرمایه‌گذاری به زیر بخش‌هایی كه از كشش جانشینی پایین‌تری برخوردارند می‌تواند میزان اثربخشی ابزار سرمایه‌گذاری بر ایجاد اشتغال در بخش كشاورزی را بهبود بخشد.
چكيده لاتين :
Introduction: On the approach of job creating oriented policy, taking the determinants which affect on the job creation power of investment into account, can play very effective role in enhancing the policies results. The elasticity of substitution and return to scale are two important factors which affect the efficacy of investment in job creation. Theoretically, it could be inferred that the lower the elasticity of input substitution, the higher the effectiveness of investment expenditure in the creation of job opportunities for labor forces. On the other hand, the efficacy of investment in job creation will be increased if there is increasing in the degree of return to the scale of production. This paper aims to investigate the contribution of return to scale and elasticity of substitution to the efficacy of investment in job creation in Iran agricultural sector.
Materials and Methods: Different econometric methods were applied to analyze the data and to estimate the presented models in this paper. Augmented Dickey Fuller (ADF) method was used to test the stationary of variables and showed that all variables are I (1). The co integration between variables was tested using Jonson Co integration approach. Jonson Co integration test results rejected the hypothesis of no Co integration between the variables of the estimated models. The values of elasticity of substitution and return to scale have been calculated for the agricultural sector by estimating the coefficients of the per capita production function using Calman Filter approach. This approach was also used to calculate the effect of the investment on employment by estimating the coefficients of the labor demand function in the agricultural sector. Next, the contribution of the elasticity of substitution and return to scale to the effect of the investment on employment in the agricultural sector has been estimated using three estimation methods including ordinary least squares, robust least squares, and generalized linear models. Required date, including agricultural sector production, agricultural sector capital, agricultural sector employment, agricultural sector wage index and interest rate were gathered from Iran central bank, and Iran statistics organization during 1974-2012.
Results and Discussion: The estimation results of per capita production function in agricultural sectors show that the coefficient of labor in estimated per capita production function is negative. This reveals the existence of decreasing returns to scale in this sector during the studied period. The agricultural sector has also experienced low levels of elasticity of substitution during the period and there was no significant fluctuation in the trend of substitution elasticity. According to the estimation of labor demand function for the agricultural sector, variables like investment, production and interest rate have statistically positive effect on labor demand in this sector. Wage index, however, negatively affects the labor demand and employment in the agricultural sector. Estimating the effect of a return to scale and the elasticity of substitution on the employment effects of investment, by robust least square, reveals that one unit increase in the return to scale index leads to 0.02 unit increase in the effecting coefficient of investment on employment in the agricultural sector. The elasticity of substitution, however, has a negative effect on the effecting coefficient of investment on employment, so that one unit increase in elasticity of substitution leads to 0.077 unit decrease in the effecting coefficient of investment on employment in the agricultural sector. Ordinary least squares and generalized linear models estimation also show that a one unit increase in the return to scale index leads to 0.009 unit increase in the effecting coefficient of investment on employment in the agricultural sector. Elasticity of substitution, however, has a negative effect on the effecting coefficient of investment on employment, so that one unit increase in elasticity of substitution leads to 0.06 unit decrease in the effecting coefficient of investment on employment in the agricultural sector. All findings are in line with theoretical expectation and verify the positive role of return to scale and negative role of elasticity of substitution on the employment effects of investment in the agricultural sector.
Conclusion: The policy making the implication of the findings is that the allocation of investment to agricultural subsectors with a higher degree of return to scale and lower degree of substitution elasticity, would enhance the efficacy of investment in job creation in the agricultural sector. Improving factor productivity via integrated the agricultural lands and utilizing new irrigation systems, in this regard, lead to enhance the degree of return to scale and increase the job creation potential of investment in this sector.
