The number and type of cases for which interviews and housing inspections are to be carried out should reflect the reviewer's judgment based on the information he has just reviewed. Generally, an interview and inspection should be carried out for at least one of every five cases for which the files and records have been reviewed. Only where the number of persons displaced is less than 25 should the number of interviews and inspections be less than 10. In no case should the number of interviews and inspections be lower than the lesser of five and the number of persons displaced. To the extent possible, the interviews should cover a representative cross section of the types of cases in the agency's workload: e.g., relocation cases involving families of various sizes as well as individuals and business concerns (including both owners and tenants), and acquisition transactions involving residential, commercial and industrial properties.
Cal. Code Regs. Tit. 25, § 6060