Data Analysis with IBM SPSS Statistics

Using aggregation to add fields to a file

A dataset contains information that is readily evident in the fields themselves, but it also has useful content that is inherent in data. Often, it is important to place specific values in a broader context to make them more meaningful. Personal income, for example, can be an important predictor in many situations but comparing someone's income with the average income in their area provides a more nuanced view of their relative economic situation. Similarly, a student score on a reading test can be compared to the national average but it is also useful to compare their score with other students in their district or school. A student's score may be just slightly preceding to the national norm but they ...