# Calculating DESSA Change Scores

Instructions for Using the Templates for Calculating DESSA and DESSA-mini Change Scores

The purposes of the Excel templates are to aid programs in calculating the difference between a child’s pre and posttest DESSA T-scores and also a child’s DESSA mini scores.  The templates can be used to evaluate the magnitude of the differences between rating periods.  The magnitude of T-score differences are based on Cohen’s d-ratio and include:

Magnitude of DifferenceT-score Units
No changeLess than 2
Small2 to 4, inclusive
Medium5 to 7, inclusive
Large8 or higher

The excel spreadsheet (Template for Calculating DECA Change Scores – Positive and Negative) calculates and evaluates both positive and negative differences in a student’s pre to posttest T-scores.  For example, a difference of 4 points between pre and post test would display as Small Positive Change; difference of -7 between pre and posttest would display as a Medium Negative Change

The Excel documents contains two sheets. The sheet labeled “Data” is where your program’s data can be entered. The sheet labeled “Graphs” contains summary presentations of your program’s pre and posttest DESSA scores, as well as a look at the overall change categories from pre to posttest shown by children in your program.

1. Enter your program’s data on the “Data” sheet. Columns are provided to enter child name or ID, dates of ratings, rater names, and pre and posttest DESSA T-scores.
2. Once a pre or posttest T-score is entered, the pre and posttest DESSA categories will automatically be filled. T-scores of 60 and above will be identified as “Strength” and the cell will be colored green, T-scores of 41-59 will be identified in a blue cell as “Typical”, and T-scores below 40 will be identified as “Need” and shaded red.
3. Once both pre and posttest T-scores are entered, the “Change Score” and “Categories for Change Scores” columns will automatically populate based on Cohen’s guidelines.
4. To see an overall summary of your program’s scores, refer to the “Graphs” sheet. Summary data has been automatically compiled for your program based on the data you’ve entered.

*The automatic columns on the “Data” sheet have been locked to protect the formulas. If you need to unlock this sheet for editing, please contact Jennifer Fleming for the password at [email protected].