Then, the corrective actions will be taken to improve overall project performance ultimately. Moreover, measurement will be only considered effective when it is reporting on the risk levels and also investigating the reason of exposing to current risk level. The main intention in measuring safety and health performance is providing information on the progress and current situation of site activities to control safety and health risks. The safety performance is traditionally measured by using statistic data of injury and fatality. The finding of a research indicates that construction worker has three times more higher chances of dying and two times higher chances of getting injured compared to the workers involved in other industrial activities. Construction works are well known as one of the most dangerous and risky activities throughout the world because large amount of people are being killed and injured every year. Measurement of safety is primarily look at the amount of accidents occur during construction period. Safety and health is stated as the degree to which the general conditions promote the completion of a project without major fatalities or injuries. However, quality performance of the products and services which have been received by client within cost and time is always tightly related to the measurement of clients' satisfaction. They must always show improvement in the performance if they want to survive and sustain in the global marketplace. The findings also show that construction companies can increase their profits by 100 percent if they are able to retain five percent or more from the existing clients.Therefore, clients' satisfaction is one of the key performance indicators for all the participants in construction industry. There is a research suggesting that to build up relationship with a new client in construction industry is five times more expensive than to maintain existing one. Usually, clients of construction sector experienced dissatisfaction in many aspects including overspend in project cost, delay of completion, poor quality, and incompetent project teams like subcontractors and consultants. Client's satisfaction has become challenging issue for the past few decades in construction industry. Satisfaction has been explained as a function to make comparison between a perception of an outcome by an individual and the expectation of the outcome. The formula of the elements and indication are shown as follows. Besides cost variance, cost performance index (CPI) also has been used to measure performance of a project for the reliability and the confidence of results. Furthermore, the element of cost also has been suggested to measure the performance in engineering projects. Besides, Cost variance has been used in a research as the measurement for project performance in a construction project which has problems of defective design.

Cost variance is measured in terms of unit cost, percentage of net variation over the final cost. The overall costs comprise all the costs involved in variation work or modification work and also the costs involved in any legal claims such as arbitration or litigation upon the construction period. Moreover, cost variance technique is not only limited to the calculation of the tender sum but also includes the overall costing that incurs in a project from commencement to completion. The cost variance is the technique usually used for design performance measurement of a project in construction industry. It is stated as the degree to which the general conditions promote the completion of a project within the estimated budget. There are cost performance, time performance, quality performance, safety and health, and clients' satisfaction. Hence, there are five major variables that have been identified to measure projects performance. At the same time, some researchers also noted that there are other various key components such as design performance, safety and health, performance of environmental management, expectation or satisfaction of the end user, client's satisfaction, and commercial value that are used in project performance measurement. Those criteria include meeting the budget, schedule, quality of workmanship, stakeholders' satisfaction, safety and health, and transfer of technology. On the other hand, there are other criteria that have been suggested to be considered in a project. Moreover, these three major components are noted as “iron triangle” (see Figure 1) according to a researcher. Generally, it has been widely accepted that time, cost, and quality are the major concerned factors in the performance measurements of a project.

Likert scale project success thesis