The purpose of this report is to increase understanding of the achievement levels for the National Assessment of Educational Progress (NAEP), what they are, and what they are not. NAEP is a survey of American students' knowledge and skills in different subjects at grades 4, 8, and 12. NAEP combines the samples of performances to provide information about the knowledge and skills of students in the nation as a whole, in each participating state, and in different demographic groupings. This overview of the NAEP Writing Framework details what is assessed by the Writing NAEP--the framework is the guide to the assessment, and it represents practices and skills that are considered essential for good writing. Proficient achievement is defined as "solid performance exhibiting competency over challenging subject matter"; the Basic and Advanced achievement levels are defined relative to this central level. The report is divided into the following sections: Understanding Achievement Levels for the Writing National Assessment of Educational Progress; Overview of the Framework for the National Assessment of Educational Progress in Writing; Achievement Levels: Descriptions and Cutscores; Achievement Levels: Sample Items; and Performance Data. (NKA)