Authorizers are as varied as the schools they oversee. Some are responsible for just one charter, while others monitor hundreds of charters serving tens of thousands of students. Some are school districts, while others are independent statewide boards, universities, not-for-profits, or state education agencies. Regardless of their size and type, authorizers must do the important work charged to them by law: deciding which schools should open, monitoring and supporting their progress, and closing those that fail to serve students adequately. There is an emerging consensus on specific authorizer practices that are necessary to do the job well. The National Association of Charter School Authorizers (NACSA) has created and refined "Principles & Standards" that reflect this consensus. Drawing from that, NACSA has crafted a 12-item "Index of Essential Practices" that provides a baseline measure for authorizers. An individual index score (from 0-12) is a diagnostic tool, and can be used to scan the work across the entire sector. The index score communicates to authorizers if they are doing these essential, key pieces of work. This information can then help begin a dialogue about improving practice. Appended are: (1) Methodology; and (2) NACSA Resources for Authorizers. (Contains 4 footnotes.)