If electronic monitoring is not possible, verification callbacks must be done each month. If resources are insufficient to do both, verification call-backs can be discontinued as long as monitoring is done in an optimal fashion. A telephone line monitoring system is used that allows both the interviewer and the respondent to be heard. A CATI system is used and the administration of the questionnaire can be replicated and viewed at another monitor. The monitoring system is unobtrusive, that is, there is no line noise and persons monitoring are not in sight of the interviewer.
Monitoring is done systematically for all interviewers at least once every month.
An additional third step is required when electronic monitoring is regulated by state law. The interview may be monitored for quality assurance purposes, but all information obtained in this study will be confidential.