The No Child Left Behind Act sanctions the use of NAEP scores to confirm state testing results. The U.S. Department of Education, as test developer, is responsible to set forth how NAEP scores are to be interpreted and used. Thus far, the Department has not published a clear set of guidelines for using NAEP achievement level scores to conduct a confirmation analysis. The lack of an official guidance document, however, does not mean that the issue has been ignored. This study searched the literature from the Department and from other sources to locate principles or "ground rules" that inform and guide confirmation analyses. The basic principles that the study identified do not exhaust all factors relevant to conducting a confirming analysis. Taken together, however, these principles provide researchers ample direction regarding the valid use of NAEP achievement level scores. They include: (1) NAEP's definition of Proficient is not synonymous with proficiency in a subject; (2) Confirmation should not be conducted on a point-by-point basis; (3) Differences between NAEP and the state testing program must be explored and reported; (4) NAEP's percentage at or above Basic is the most directly comparable statistic for confirming state AYP results; and (5) Plotting and comparing "proficiency trend lines" from NAEP and the state test is a defendable method for using NAEP to confirm state results. (Contains 1 table, 2 figures, and a Power Point handout.)