Below is a link to a thought-provoking article that appeared in ASCD's October 2013 Education Update (Volume 55, #10). The link gives a short preview then calls for you to log in as an ASCD member. Thanks to Powell Middle School principal Jeff LaPerriere for discussing this article at our group's January 2014 PLC Self-Help Meeting
http://www.ascd.org/publications/newsletters/education-update/oct13/vol55/num10/How-We-Got-Grading-Wrong,-and-What-to-Do-About-It.aspx
http://www.ascd.org/publications/newsletters/education-update/oct13/vol55/num10/How-We-Got-Grading-Wrong,-and-What-to-Do-About-It.aspx