Summary reports of student assessments often include the percentage of students who score at and above (or below) certain proficiency levels or benchmarks. This type of data is often included with curriculum based measures such as DIBELS or AIMSweb or with annual tests administered by state departments of education. Occasionally consumers also might be told the percentage of students scoring at or above a given percentile.

Sometimes consumers are given information on the mean, or average, score obtained by a group of students. These reports also typically include the standard deviation. When comparing results for a school to a larger entity, such as a national norming sample, users need to know the standard deviation for the larger group. When comparing average scores between two groups of the same type, the user needs to know the standard deviation of both groups.

The third type of data used by the EIC is the percentile rank of the average student. The EIC translates percentiles to Normal Curve Equivalent (NCE) scores before calculating the output statistics. Users are advised to use the two other types of input data rather than percentiles if these other data are available.

To use the EIC it is not necessary to know the sample size. However, if this information is inputted the EIC will report the probability that a result occurs by chance. When users compare data for their group to a larger entity they only need to know the number of students tested for their group.

 See Technical Report 2016-2 for more details on the input statistics. Click Here