Take the track and field events of Beijing Olympic Games as an example. After four big exams, the suitable candidate was basically determined. The first round of assessment began in Yixing in 2005, and all the 400 referees who signed up participated in the first round of assessment.
After a week of business training and assessment, 40% of the participants were eliminated. The second training was held in 2006, with more than 300 participants. After the training, there are more than 200 people left. At the beginning of 2008, only 40 key referees (presiding judges and referees) were trained.