On 18th May 2019, the whole research team visited Khaosok Rubber Fund Cooperative Ltd. 66 , Tambon Khaosok, Nongyai, Chonburi 20190. The purpose of the visit was to have a focus group discussion with the Rubber Cooperative in order to understand current situation of smallholder rubber farmers in the area and their diversification activities. This included an overview of the economics of the rubber production in the area, diversification and intercropping activities practiced by the cooperative members. The discussion with the manager of the cooperative lasted for 3 hours. The discussion enabled the research team to develop an in-depth understanding of smallholder rubber farmers' situation and informed further development of the questionnaire to collect information for linear programming of rubber farmers' decision making on diversification.