The National Assessment of Educational Progress (NAEP) item development procedures, possible improvements or alternatives to these procedures, and methods used to control potential sources of errors of interpretation are described. Current procedures call for the assessment of 9-, 13- and 17-year-olds in subject areas typically taught in schools. Objectives and items are developed and reviewed through a consensus process which involves subject-matter experts, educators and lay persons. Reviews help to establish the accuracy and content validity of items and to guard against potential item bias. Procedures used to prepare item booklets, administer the assessment and score the items are designed to reduce sources of error and to ensure nearly identical conditions across assessments so measurements of change are accurate. Possible alternative procedures, including structuring assessments by means other than subject areas, using an assessment framework other than objectives, developing objectives through textbook analysis, employing objectives developed by other organizations, using a contractor other than NAEP to monitor development and changing the number or type of reviewers, are also discussed. Procedures that would benefit from further research are identified. (Author/RL) Primary type of information provided by report: Procedures (Exercise Development) (Objectives Development).