Professional development that improves teaching and student learning meets research-based standards to ensure high-quality educator learning experiences. Since the quality of professional learning affects its results, many states, districts, and schools want to measure the effectiveness of their professional development to make targeted improvements. However, few valid and reliable instruments are available to provide this information. The Standards Assessment Inventory (SAI) helps schools and districts assess how well their professional learning practices align with the National Staff Development Council's Standards for Staff Development. The results can help educators focus on ways to improve the quality of their professional learning and create overall school improvement that contributes to student achievement. NSDC partnered with SEDL, a national education research laboratory, to design and produce a valid instrument that reliably measures how well a school's practices meet the definition of high-quality professional development. The SAI measures each of the 12 standards with five questions. The completed instrument provides data that educators can use to identify areas of strength and areas that need improvement. Using the SAI results, along with processes and strategies included in this document, districts can determine their next steps in planning for continuous professional learning focused on increasing student achievement.