To be sure that students can meet expectations, they must know what they are. Sounds obvious, but most syllabi don’t have formal rubrics. Students need to know their grades aren’t dependent on your mood. Yes, they sometimes think this!
Some sample rubrics are here. Feel free to make small tweaks to customize for your own assignments. Be sure to include a rubric in every syllabus.
In 2012, as part of the Middle States assessment process, new rubrics are in place for core courses. Full details are in the Program Assessment Manual.