Essentially, to assess and grade effectively, educators must let go of personal experiences "when I was a student", which perpetuates the broken model, and become a pioneer, exploring new territory with an open and fresh perspective.
There is good literature available that focus on engaging educators to reflect on the quality of current practices, and explore new ways of thinking--with an open mind.
Two books that make for a strong reflective exploration of grading are by Rick Wormeli and Ken O'Connor:
Wormeli, Rick. Fair Isn’t Always Equal: Assessing & Grading In the Differentiated Classroom. Stenhouse Publishers: 2006
Address quality elements of good assessment and grading practices based on getting an accurate understanding of student learning. Provides strategies and different views for thinking and methods for effective assessment and grading. Great for teachers and administrators. Makes for an excellent book study for schools and districts looking to build clarity in assessing student learning.
The author shows how to link grades and standards. His eight models assist teachers in designing and conducting grading practices that help students feel more in control of their academic success. This eye-opening dialog remains an exceptional way to begin a journey with even the strongest skeptics.
Ken O'Connor wrote a book that is my personal favorite because it tackles the most difficult issues. Many of the challenges that educators have difficulty digesting tend to be more about control then the deeper issues that need addressing in a constructive, positive, and clear intend for what is best for clean assessment and the development of the learner.
O’Connor, Ken. A Repair Kit for Grading: 15 Fixes for Broken Grades; 2nd Ed. ATI: 2010
Teachers and school/district leaders gain a deeper understanding of the issues involved in sound grading practices. Includes: practical strategies and alternatives to help change how students are graded.
I intend to explore some of the concepts in this last book with the hope to encourage a rich dialog about where grading needs to play an effective role for student achievement.