# Quick data guide

## Accuracy and speed

For each CoPS subtest, results are calculated automatically and are shown both for accuracy (black dots on the report) and speed (blue dots on the report). Of these, accuracy is usually the most important indicator.

## Standard Age Score

CoPS results for both accuracy and speed on each subtest are given Standard Age Scores (SAS). Standard Ages Scores (SAS), like IQ, are usually expressed with a mean of 100 and a standard deviation of 15. These scores reflect the student’s performance compared to those of the norm referenced group, which is based on the student’s age, in three-month age bands from 4:0 up to 7:11.

## Confidence bands

This gives an indication of the range within which a student’s score lies. The dot on each subtest row within the table represents the student’s SAS and the horizontal line represents the 90% confidence band. The shaded area shows the average score range.

## Stanine

This places the student’s score on a scale of 1 (low) to 9 (high) and offers a broad overview of performance.

## National Percentile Rank

This related to the SAS score and shows the percentage of students obtaining a certain score or below. An NPR of 50 is average since 50% of students obtain an SAS of 50 or below. An NPR of 5 indicates that a student’s score is within the lowest 5% of the nationally representative sample and an NPR of 95 means that a student’s score is within the highest 5% of the national sample.

## Z-score

Z-scores show us the student’s score in standard deviation units, with a mean of 0 and an SD of 1. So, a Z-score of -1.0 would indicate that the student’s score is one SD below the mean and a Z-score of +1.0 would indicate that the student’s score is one SD above the mean.

## T-score

T-scores have a mean of 50 and a Standard Deviation (SD) of 10, so a T-score of 40 is one SD below the mean and T-score of 60 is one SD above the mean. 68% of T-scores would fall within the 40-60 range, so a T-score below 40 would be considered below average and a T-score above 60 would be considered above average.

The relationship between these scores is shown in the figure below:

## Guidance for interpretation table

The Guidance for interpretation table on the report provides enhanced guidance for interpreting each student’s results. Match the guidance to the CoPS Indications for Action table found here. Interpreting the results from CoPS requires interpretation of the overall profile, and not just the consideration of each individual subtest separately. Please see the Case Studies for further guidance on interpreting the whole profile.