Methodology

Schools & Students

School information is from the SDP open data records, student enrollment numbers are for the 2012-2013 school year.

Textbooks & Inventory

Source of our textbook data: We received from the School District of Philadelphia a PDF, 1338 pages long, that contained a data dump from the SDP Textbook Storage System. This includes all textbooks in use; it does not include library books. More info on the system is at http://webgui.phila.k12.pa.us/offices/e/etg/textbook-storage-system and a history of the need for this system is at http://webgui.phila.k12.pa.us/offices/e/etg/textbook-storage-system

Textbooks are gathered from the inventory records. Because of inconsistent title data from inventory records, we found title and publisher information by querying against reputable book databases, with about 60% of our book information coming from isbndb.com and the remainder from the Amazon and AbeBooks product APIs. When prices/curriculum associations were added, the titles were updated to how they are referenced by the publisher/curriculum.

Curriculum

The state of Pennsylvania has approved curriculum, and the School District of Philadelphia has negotiated prices for the various curriculum and has approved them for the school types (empowerment and non-empowerment). This is where the prices as detailed in the price gap come from.