1. A method comprising: retrieving a first document from a data source, the first document having a first data item and an identifier; generating a first hash value based on the first document; integrating the first data item into a knowledge model in a data storage device; retrieving a second document having the same identifier as the first document and having a second data item; generating a second hash value based on the second document; comparing the first hash value to the second hash value to determine whether the second document is different than the first document; replacing the first data item with the second data item in the knowledge model if the first hash value is different than the second hash value, or maintaining the first data item in the knowledge model if the first hash value is identical to the second hash value; and displaying from the knowledge model either the first data item or the second data item.