At a PAP rally on 7 September 2015, Vivian Balakrishnan also called to attention Chee's role in ousting Chiam See Tong as secretary-general of SDP in 1993, saying that the PAP "did not have a tradition of "backstabbing" its mentors". In response, Chee, as well as the SDP's Marsiling-Yew Tee GRC candidate Bryan Lim, provided an account of the incidents that led to Chiam's resignation on the party's website, saying that Chiam resigned on his own accord. Lina Chiam, Chiam's wife and the chairperson of Singapore People's Party (SPP), confirmed that the two sides had held "friendly talk" on the issue. At the same PAP rally, Sim Ann accused Chee of being adept at "chut pattern", a Singlish phrase meaning being full of antics. Chee responded the following day at a SDP rally by stating that he would not respond to personal attacks and would stay focused on policy issues during the election season, saying, "If you attack, you attack the policy, not the person... In football terms, you play the ball, not the man." Chee also addressed the different target population figures cited by government officials in the past, including the much debated 6.9 million figure in the Population White Paper, asking if the PAP would consider the SDP's proposal to base the optimal population on the happiness of residents, and a point system when bringing in foreigners for skilled jobs.