For each NAEP background and cognitive item, the unweighted and weighted percentage of students who gave each response, the percentage of students who omitted the item, and the percentage of students who did not reach the item are examined. The number of respondents is also tabulated. The percentage of students in each category defined by the variables used in sampling and weighting and those collected by the assessment administrators are also scrutinized. These preliminary analyses are conducted within grade cohorts and within major reporting categories. If unexpected results are found, the item data and the coding of responses are rechecked.