Here is a guide that provides basic information to help teen/youth services librarians, library directors, library school students studying teen services, and middle/high school librarians examine all aspects of their teen programs and services to determine where improvement is needed. Find out what you need to develop goals and objectives for evaluation, and learn how to collect the data that will give you a realistic picture of your library's strengths and weaknesses. You will get practical examples of how to use many different types of data: numerical and subjective data, output measures, user data, circulation and collection statistics, policies and procedures, strategic plans, community needs assessments, budget statistics, program information, facility information, data about training and staff development. Start implementing your program using the data you've collected to make changes to your assessment plan, support your case for improved teen services, and plan for future teen services. You'll also learn to evaluate YA collections, teen summer reading programs, special events, and library staff. This guide comes with an explanation of the YALSA competencies, the YALSA teen services evaluation tool, and models for what excellent teen services programs should look like. Ready-to-use evaluation forms and checklists save precious time and resources and get your assessment geared up in minutes. Sarah Flowers is the president of YALSA and former chair of a YALSA task force to develop an assessment tool for library administrators and teen services librarians to use in order to evaluate an individual institution's overall level of success in providing library services to teens. She worked for fifteen years as a librarian and manager at the Santa Clara County Library in California.