A recently created Library Strategic Plan at the University of California Los Angeles (UCLA) developed by all staff, identified the need to integrate a culture of assessment throughout all levels organization to encourage data informed decision- making. The Assessment for Change Team (ACT) was formed to spearhead this cultural evolution. This case study discusses how we create an assessment culture in a large, complex institution. The UCLA Library ranks among the top academic libraries in the United States serving 45,000 students in 125 majors. It employs over 100 librarians and approximately 350 full-time staff working in more than a dozen library across campus. Library units report to the University Librarian through four Associate University Librarians and management staff. ACT reaches out to the campus community units close to the university administration whose primary jobs employed assessment. We make campus ties to create an environment that influences and is influenced by the university's efforts. In conjunction with creating these ties, we offer workshops to all stakeholders that introduce assessment as a form of change management in a judgment free environment. We use online templates that guide assessment-motivated and administratively supported teams to work toward goals that are future-oriented. The workshops create a common vocabulary that guide people in a shared understanding and common course of action using methodologically sound research. Concurrent with the use of complex, dynamically-generated templates, ACT conducts individual sessions that influence changes in its template designs. The templates evolve iteratively, which improves their quality and stakeholder buy-in. Finally, we accelerate the buy-in of assessment for change by illustrating the impact of using these tools in decision-making that results in improved effectiveness, efficiencies, and better resourcing. We continue working with administration to ensure their support, mutual understanding of group goals, and affirmed understanding of the process of goal-setting and data-informed decision making. While ACT members assist staff with planning as consultants, we do not participate in projects unless we are members of the teams or groups who have formulated an assessment. The tool we use, called Data Lake, is an internally built dynamic set of templates using Confluence that includes a guided questionnaire for planning assessment, a repository of tools, indexed connections to raw data sets, and reports on assessment projects. We see our greatest challenge as developing a sustainable environment that enables the continuation of our efforts over time and that impacts our organizational culture. ACT members are librarians and library staff with numerous other responsibilities in their respective units who can rotate in and out annually. All leaders need to keep the topic of assessment in the forefront of interest and attention among staff, many of whom feel have competing obligations and are resistant to the time commitments necessary for proper assessment.