Table 1.

WMH sample characteristics by city

City	Survey*	Sample characteristics	Field dates	Age range	Sample size		Response rate†
					Part I	Part II
Beijing/Shanghai	B-WMH/S-WMH	Beijing and Shanghai metropolitan areas	2002–2003	18–70	5201	1628	74.7
Shenzhen	Shenzhen	Shenzhen metropolitan area; included temporary residents as well as household residents	2006–2007	18–88	7134	2476	80.0
Total					(12 335)	(4104)	77.7

*B-WMH (The Beijing World Mental Health Survey); S-WMH (The Shanghai World Mental Health Survey).

†The response rate is calculated as the ratio of the number of households in which an interview was completed to the number of households originally sampled, excluding from the denominator households known not to be eligible either because of being vacant at the time of initial contact or because the residents were unable to speak the designated languages of the survey. The weighted average response rate is 77.7%.