Dissertation Series - Barriers to successful Data Mining - Inconsistent data recording

Databases are capable of storing data from many sources and as such data can be entered/recorded by different individuals/organisations, which can introduce inconsistencies into the data.

For example data mined from clothing manufacturers could compare sizes (large medium etc) although the definition of that size could range between manufacturers.  This would have to be kept in mind and factored in when understanding the underlying data.