Telephone surveys of mental health need and the unlisted subscriber.

Community surveys for needs assessment purposes have gained considerable popularity in recent years, yet the prevalence estimates of psychiatric impairment or mental health need vary widely across studies. It is hypothesized that part of this variability may reflect methodological concerns, in particular the directory listing status of respondents when telephone survey methods are employed. Using data from two independent community surveys, the mental health needs of listed versus unlisted subscribers were compared on a series of mental health scales. The implications of the differences observed are discussed both for further telephone needs assessment projects, as well as for service providers.