The State Library of North Carolina recently launched an 18-month pilot of a collaborative statewide chat-based virtual reference service, for which the authors have been contracted as program evaluators. The primary evaluation question motivating this pilot program is: "Is collaborative virtual reference an effective way to meet the information needs of North Carolinians?" This paper describes the evaluation plan, the methodologies, and the data analyses that will be employed to answer the evaluation question. The paper also describes some preliminary findings from one of the libraries participating in the service and currently offering chat-based virtual reference service.