ABSTRACT
The importance of estimating process when dealing with construction projects cannot be over- emphasized. That is why, the greatest problem facing Quantity Surveying practice globally is that of achieving a correlation between conceptual estimate and the final project cost which is often used by some employers to determine the efficiency of the Quantity Surveyor. This study was geared towards showing how different factors affect estimating process, the techniques used for such estimates and how often are the feedbacks and reviews from historical data of previous project works are updated by construction firm. Both quantitative and qualitative data were collected and analyzed using Pearson Product of Moment statistical tool to test for research hypothesis, tables containing the elemental cost breakdown of each project works and bar charts to illustrate the graphical relationship between the percentage deviation of the budgeted cost and factors responsible for such deviations. From the analysis carried out, result shows that, accuracy in estimating processes are largely dependent on factors such as change in project scope, change in client’s test, change in market prices of materials, weather condition (heavy rainfall) and sourced information from historical data etc.