Guiding the work of every Head Start grantee is the basic principle that all program services should be designed to meet the needs of families. Thus, before preparing a Head Start grant application, grantee staff conduct a community needs assessment. Then, in the application itself, staff describe the needs that exist and how those needs will be addressed by their program of services. In the assessments, many grantees note the numbers of parents who are in school or training programs and the number of mothers who are employed. In developing their programs, staff use this information to decide on the hours of service to be offered. Although the traditional Head Start day is between 4 and 5 hours long, if Head Start-eligible families have a high percentage of parents who are in school or training or who are employed, grantee staff can offer full-day services for children in order to meet the needs of those parents.