Monitoring and evaluating whether a charter school is in compliance with statutory and regulatory requirements and performing financially, organizationally, and academically requires the authorizer to examine a host of information about an individual school. Some of this information is reported by the school itself; vehicles such as self-reports, testing data, and financial audits detail indicators of the academic and organizational health of a school. While such documentation gives important information on how a school is performing, many authorizers have found that "seeing is believing" and have incorporated on-site reviews, or site visits, into their charter school oversight process. The benefits of on-site reviews are many. Site visits provide authorizers with a mechanism for verifying and corroborating information collected through reports, gauging the culture and climate of a school, gathering evidence of performance from a range of perspectives, and demonstrating the commitment of the authorizer to authentic accountability. There are a variety of models of how on-site reviews may be conducted and how they fit into the larger system of authorizer oversight. This issue brief will examine the key components of a quality on-site review as well as discuss choices to consider when designing school visits into a charter school oversight system. (Contains 6 examples and 3 endnotes.)