I get many questions about developing good rubrics.  There are some common mistakes individuals make which lead to flaws and the improper design and use of rubrics. Here are a few pitfalls.  Stay away from them!  

• Putting too many criteria in the rubric: Four to eight criteria is typically optimal.
• Using “quantity” criteria components in a rubric: For example, “Report cites 10 sources.” You can use a checklist for this. 
• Using a varying scale to judge one criterion: If the top criterion is “Sources support report’s purpose statement” and it’s worth 5-6 points, what is the difference between 5 points and 6 points? 
• Not allowing for students to see improvement: Criteria should be assessed in a way for students to see improvement in their work or skill. 
• Not connecting the assignment or project to course outcomes within the rubric: When objectives/learning outcomes are included in the rubric, students understand how the assignment or project relates to the objectives of the course. 

 There are other pitfalls, but avoid these common ones.