This is a really great presentation and video that finally got me to understand the ways in which you would create and use pivot tables. Thanks, Alice Keeler.
Pivot tables are an incredibly powerful tool for summarizing information. When looking at data oftentimes there are repeats in the information. Multiple times a students name is listed. Multiple times an assignment title is listed. Multiple times a disciplinary action was taken. To make sense of a spreadsheet with many rows of information a pivot table can make sense of the chaos.