ObjectiveTo design a concealed investigation scheme to control bias based on direct observation method, evaluate actual hand hygiene(HH) compliance among health care workers(HCWs).MethodsHH compliance among HCWs in 8 general hospitals in Beijing was performed concealed investigation in June 2016, data of HH compliance and correctness were obtained and conducted statistical analysis as well as direct standardization, then compared with HH surveillance data obtained by direct observation method in 2015.ResultsIn 2016, HCWs’ HH compliance rate and correct rate were 58.04% and 88.68% respectively. After direct standardization, ICU had the highest HH compliance rate (81.29%), emergency department had the highest HH correct rate (93.29%), neurology department had the lowest compliance rate and correct rate of HH (42.97% and 82.35% respectively); nurses had the highest compliance rate and correct rate of HH (69.02% and 92.84% respectively), cleaners had the lowest compliance rate and correct rate of HH (37.25% and 71.59% respectively); compliance rate of HH after contacting patients was the highest (71.79%) but correct rate was the lowest (88.76%), compliance rate of HH before cleaning/aseptic procedure was the lowest (43.08%) but the correct rate was the highest (93.50%). HH compliance rate of HCWs investigated by concealed method was lower than that by direct observation(P<0.05), and the extent of discrepancy in correctness was different.ConclusionHH compliance is different in the distribution of departments, personnel, and indication, it is necessary to strengthen intervention in key aspects of HH. There is a certain bias in results of direct observation on HH compliance, HH investigation methods need to be improved.