Disaggregating Data
Using the Disaggregate function
The DISAGGREGATE function in EZAnalyze allows you to summarize your data by categories that are created by categorical variables (glossary). Disaggregating data is a critical part of the No Child Left Behind legislation which is intended to close the "achievement gap" - the differential academic performance of students according to their ethnic background. The achievement gap is an excellent example of disaggregated data, as it shows how different students perform on standardized tests (the dependent variable) according to which ethnic group they belong (the categorical variable).
To disaggregate (glossary) your data, select the "Disaggregate." option from the EZAnalyze menu in Excel. "Double Disaggregation" is also explained below.
When the "Disaggregate" dialogue box appears, you will see two boxes with a list of all of the variables in your data set. The first box, labeled "Dependent variable(s)", is where you choose which variables you want summarized. You can choose one variable, or more than one. Some examples of common dependent variables in school settings are GPA, number of days absent, number of behavior referrals, and standardized test scores.
The second box, labeled "Categorical variable," is where you select the variable that tells EZAnalyze about your groups. This variable can be a numeric variable or a string variable (glossary). You can only select one categorical variable to disaggregate your data by from this list, although you may choose a second categorical variable to perform "Double Disaggregation", which is explained below. Some examples of common categorical variables in schools are ethnicity, gender, grade level, ELL status, socioeconomic status, and learning disability status.
OPTIONS: Once you have selected your dependent and categorical variables, you can then select descriptive statistic options located under the heading "statistic reported." The N is generated by default. Your options are:
Mean - For each selected variable, reports the average for all of the cases in your sample
Median - For each selected variable, reports the value that falls halfway between the highest score and the lowest score
Minimum value - For each selected variable, reports what the lowest number is
Maximum value - For each selected variable, reports what the highest number is
Standard deviation - For each selected variable, reports how far on average each score deviates from the mean
Range - For each selected variable, reports what the total number of scores are (minimum value subtracted from maximum value)
Sum - The total of all scores in the variable added together
Double Disaggregation - place a check mark in the box next to "Then by categorical variable 2" and select your second categorical variable from the drop-down box.
When you click OK, a results report will be printed on a separate sheet for your review. (click on "results report" for information on how to interpret this analysis)