The use of population-based indicators is common in extensive needs assessments and has several strengths. These strengths include that such data are available for broad geographical areas, available on a large number of individuals or cases, allow description of entire populations, allow trend analysis over time, are relatively easy to access, inexpensive to use, and perceived as unbiased. Another method commonly used in extensive needs assessments is the survey. The strengths of the survey method are: they allow for direct feedback to the public as well as stakeholders, can foster public awareness about a problem or concern, can be customized to address specific issues, can be targeted to specific population groups or geographic areas, and can provide very timely results. An additional potential data source for extensive needs assessments are service and program databases. The strengths of this source of data are: they often contain data collected over many years, are readily accessible by existing program staff, provide the most current data, and they are relatively inexpensive to operate and maintain.