المفاضلة بين نماذج انحدار البيانات الطولية في تقدير و تحليل دوال الاستثمار للقطاعات الاقتصادية الإنتاجية في العراق للمدة (1995-2016)‎

الملخص EN

JAE.42.2019.122.24398economy in order to provide accurate economic indicators that help the Iraqi plan toallocate resources to the investment process at the level of productive economic sectors.

The results of the standard analysis showed that the random effects regression model(REM) is the appropriate model for research and is best for estimating the function oftotal fixed capital formation at fixed prices for productive economic sectors using theGLS method.

And that the estimates of the features were more efficient and significantthan the resulting estimates using the time series data for each sector according to theOLS method, as this model resulted in a decrease in the value of the estimated valuevariance.

It also showed that there is a long-term balanced relationship (co-integration)between the research variables, which are directed from the explanatory variables towardsthe dependent variable through the application of tests (kao, pedroni) for the simultaneousintegration.

The results of the standard analysis through the application of the REM model showedthat the total fixed capital formation is an important variable and an indicator in thenational economy in general and in the productive sectors economies in particular, as itsvalue is determined in any year during the research period by the size of the grossdomestic product and the size of the total capital formation The fixed money for theprevious year (t-1) in varying proportions and according to the importance of the sectorin the national economy.

Key words: aggregate regression model; fixed effects regression model; random effectsregression model, investment functions; unit