At present, about 20 HIA case studies have been conducted in Thailand. The first version of HIA guidelines was introduced at the National Health Assembly in August 2001 and accepted as one of the core elements of the National Health Act. To create the critical mass, HIA training courses have been based on participatory learning techniques, such as role – playing and simulation, tailored to different situations and target groups. Examples of case studies and training courses are shown in Table 2.