ISLLC Standards Policy Update Image. Click Image to Download ReportMost states base their standards for school leaders on the Interstate School Leaders Licensure Consortium (ISLLC) standards. These standards were updated last November. This NASBE Policy Update compares the new standards, now called Professional Standards for Educational Leaders (PSEL), with the ISLLC standards and outlines what states will need to consider as they implement changes instituted by the Every Student Succeeds Act (ESSA).