Abstract: Contract flexibility has an important effect on the contractor's performance of a contract in an environment where uncertainty hangs over construction projects, but there is a lack of empirical evidence for the specific mechanism. Based on the existing literature, this paper divideds flexible contract into three dimensions, i.e. price, control rights and negotiations. Furthermore, project information transparency is introduced as a moderating variable to verify the amplifying effects between the three dimensions of contract flexibility and the contractor's perfunctory performance behavior or consummate performance behavior. The collected questionnaires are analyzed by using partial least square method. The results show that when the information transparency is at a high level, price flexibility, control rights flexibility and negotiations flexibility have a positive impact on the perfunctory performance, particularly with the control rights flexibility having the strongest impact. In addition, the transparency of information plays no role in moderating the contractual flexibility and the contractor's consummate performance behavior. Finally, the control rights flexibility and the renegotiation flexibility have a significant positive effect on the contractor's consummate performance behavior, but the price flexibility does not. Our study sheds significant light on the theoretical study of contractual flexibility in construction project and provides a theoretical basis for the design of flexible contracts for clients and contractors.

Key words: contract flexibility, contractor's perfunctory performance behavior, contractor's consummate performance behavior, information transparency