2.1 Definition of Risk
In past research, researchers have defined risk according to their perspective and understanding. Based on Jaeger et al. (2013), risk entails both possibility that an outcome or event can happen with the denial that either occurs with predetermined certainty. Risk includes both good and bad impacts, which are referred to as opportunities and threats (Lehtiranta, 2014). As per Gokmen (2014), risk is defined as the possibility of an action or activity to bring into damage or loss and to determine, evaluate, and give priority to the unexpected outcome.

In the context of project management, risk is referred to as the measure of the likelihood and the consequences of not fulfilling a project goal (Koleczko, 2012). In the construction context, Thomé et al. (2016) define risk as the variance of either cost or time estimates, where it is measured by the likelihood of the event with the impact of the risk if occurred. Risk is closely tied to human nature which it involves option among discrete possibilities. Predicting the aftereffect of alternative possibilities, assessing their benefit, and choosing the most desirable choice lie at the core of human agency (Jaeger et al., 2013). Risk is, therefore, a social concept effected by various kind of discrimination. The idea of risk was created by human, so there is no such thing as real risk or objective risk (Sotic et al., 2014). In the context of uncertainty, risk has today become an expression (Johansen and Rausand, 2014). In other studies, risk is related to the difference of the expected uncertain consequences. Therefore, risk presents the chance or likelihood of contrast outcomes than the predicted ones (Hartono et al., 2014).

Researchers argue that there is no comprehensive meaning for risk as the literature presents a various understanding of risk (Lehtiranta, 2014; Aven, 2012). According to Aven (2012), the definitions differ; while some focus on probability and likelihood, others focus on undesired consequences and threats and some line risk with uncertainty.