نموذج قياسي كلي للإقتصاد اليمني

Abstract

Abstract This study is based on designing a holistic a macro-econometric model of Yemen in with the aim of predicting the future trends of the economic variables in Yemen and to reach the required rate of growth of the economy and identify the investments that should be available to achieve this growth. The model was constructed based on four standards namely; the economic theory features and structure of tlle Yemeni economy, utilizing or benefiting from the previous evaluative research conducted in Yemen and the extent to which the data were available and were detailed. The model is based on a time series of annual data for the period (1990-2008) which are of a real value. The model is also characterized with its dynamic nature as it consists of lagged variables, and it employs the dummy variables to take into consideration the structural variables and political circumstances in Yemen. It also encompasses 41 equations including 16 behavioral equations. The current study models are placed in four major blocks which constitute the supply and demand sides of Yemeni economy which are the real sector, the govermnent sector, the monetary sector and the external sector. For estimating the model, two phases were performed: The first stage: In this phase, the solution of the behavioral equations was conducted by using ordinary least squares (OLS), and the model estimation was a difficult and challenging as it included numerous attempts in order to reach to the final form which can be consistent with the economic theory, and by which, the standard and statistical tests and the specificity of the structure of the Yemeni economy. The second phase: Model Stimulation: The second phase began with identifying each equation of the model and placing them in the Simultaneous Equation Model. D

It also includes solving the entire equations of tlle model fully using the three — stage- least squares (3 SLS). After carrying out the process of identifying the model to determine the appropriate way of estimating the model, it was found that each behavioral equation with over loft diagnosis meets the requirements of tlle necessary condition for the diagnosis, which is the Order Condition. After carefully reviewing the values of the variables (equations), and subjecting them to well- known statistical tests to ensure the reliability of the estimates and their conformity with the expectations of the theoretical side, the final model was determined. After the completion of the estimation, the suitability and validity of the model were tested by carrying out dynamic simulation for the period of time (1990-2008) upon which the model was constructed and tested by using a group of criteria to measure the extent of the deviation between the estimated numbers and the actual figures of the intemal variables. The model simulation and tests showed that the majority of the variables of the model achieved satisfactory results, and the model managed to largely simulate the historical and actual or real pattern of the major variables, and based on such findings, the model can be used to achieve a number of goals including: -Predicting the future trends for the macro-economic variables of the Yemeni economy for the period (2009-2020). -Estimating the required rate of growth of the economy (44%) of the value of the GDP. -To achieve the required growth, investments need to be estimated (3,548,613) million YR. -Recognizing the impact of implementing certain policies and alternatives through simulation.