According to the survey of "migrant workers employment trends research" team, Tsinghua University, on 2043 migrant workers, 65.9% of them have ever changed jobs; 25% have changed jobs in the past 7 months, 50% in the past 1.75 years. Migrant workers generally change their jobs every two years on average. However, one third of them fail to make improvement in pay, skills or position. Although 42% of them can make more earnings after changing job, only 11% have achieved progress in skills, while 15% say they did not make any improvement in terms of pay, skills or future development. The report says that employment of migrant workers is faced with a shortage tendency, which is indicated in two aspects, that is, "high flow" and "horizontal level".