Integration of cost control and estimation using Spreadsheets and databases

Abstract

Cost control is very important for any industry, since it is the activity which monitors the actual cost against the budgeted costs and initiates corrective actions if the costs are higher than expected. The estimating activity produces the anticipated cost or the budget and it is advantageous if the cost control activity could be linked to the estimating process. Computers can be effectively used to link the two processes, maximising data sharing and forwarding. In Sri Lanka most of the construction companies do not have integrated estimating and cost control systems in order to improve their performances although there are some " off the shelf packages" available in the market for independent activities. Therefore, it is required to conduct research and development in this area. As a first step, it is advisable to use readily available general software such as spreadsheets and databases and develop low cost system to address the need. This paper presents research work undertaken at the Department of Civil Engineering of the University of Moratuwa to develop a simple cost control system (using a database) linked to an estimating system (in a spreadsheet environment). A detailed study of existing literature on estimating and cost control was carried out and the concept for integration was established. Collection of cost data at site level is tiecessary for cost control, hence cost collection data sheets were designed to gather cost information at sites daily and enter to the system weekly to produce reports. It was decided to collect the maximum amount of data with minimum paper work since personnel at work sites are generally reluctant to undertake additional paper work. A cost control system was developed using Microsoft Access® and was linked to the estimating system, which is in the Microsoft Excel® environment. A test run was successfully carried out using a two storied building as an example. The system produces four reports for variance analysis for the most recent week, variance analysis for the whole period, percentage of work completed and cost details (breakdown of cost under major cost areas) for each BOQ item under construction. This information helps to monitor the behaviour of work in a better way.