نمذجة أثر تغيُّر سعر الصرف على أسعار الأسمنت في السودان (2000- 2016)

Abstract

Feasibility studies, planning, pricing and contract management in the construction industry depend mainly on the stability of the economic process where most infrastructure projects require relatively long periods of time to implement them. In a highly inflationary economy where foreign exchange rates constantly change compared to the local currency for long periods that may extend for years. In such an economy, the prices of construction materials vary according to market variables. The methods of pricing items in bids are not feasible for profit and loss accounts and for competition purposes, which leads to significant complications in the management of construction contracts associated with these projects and generates a new case of continuous change unprecedented and has not been resolved even in the global construction contracts of FIDIC. The researcher monitored and collected the inflation values and the exchange rate of Sudanese pound against US dollar as the main currency for a large number of years against the prices of cement for the same years and then statistically studied through a number of statistical analysis programs. Information has been studied over time and then the change in the price of cement versus inflation and the exchange rate and a try to devise a function has been carried out in order to describe that change and express it in a mathematical formula that facilitates reading, analyzing and forecasting. It was found that the change of cement prices is related in a logarithmic function with both inflation and the exchange rate. The independent explanatory variables (exchange rate and inflation rate) were found to be responsible for at least 80% of the changes in the dependent variables (cement prices). The remaining 20% is the impact of other (random) variables not included in the model, and this is an indication of the quality of the documentation of the model. That the variables included in the model is the most influential in the dependent variable of non-included variables. The mathematical models have passed derived economic and standard criterion and have been acceptable statistically and can therefore be relied upon to test any hypotheses are developed.