Many different ingredients go into good writing, from smooth sentences to correct capitalization. But no writer can keep every single ingredient in mind all at once. Instead, it's easier to consider three key qualities: structure, ideas, and conventions. All writing—from paragraphs to essays to reports, stories, and so on—should exhibit these qualities.
Structure
Good writing has a clearly developed beginning, middle, and ending. Each main point and supporting detail is arranged in an order that is easy to follow.
Ideas
Effective writing presents interesting information about a specific topic. The ideas are thoroughly developed through supporting details. And these details are presented using strong sentences and specific words.
Conventions
Good writing follows the basic standards of punctuation, capitalization, spelling, and grammar. It is edited with care to ensure that the work is correct and easy to follow.
You may have noticed that the qualities are a simplified version of the traits of effective writing—ideas, organization, voice, word choice, sentence fluency, and conventions. While the traits have provided the foundation for state writing standards for more than 50 years, the Common Core focuses on just three of the traits (ideas, structure, conventions) for students in grades K through 5. We call this reduced list of traits the "qualities" of effective writing.
You can use these rubrics to evaluate writing for third-grade students.