"The chances of [common data formats] happening are remote, because the databases are from two different sources anyway," he said.

Hydrasight research director, John Brand, said large integration projects associated with mergers and acquisitions are a CIO's "worst nightmare", because of the sheer complexity of the data sets.

"There is a misconception that a customer is a customer is a customer," Brand said. "When you get complex relationships between customers, and the contracts they have, vendors struggle with integrating those."

Brand said vendors give a "good impression" of integration, but it is just an initial step that, once overcome, gives users a path to integrate the data.

"What constitutes a customer is more complex than a name and address; whatever data environment you are migrating to must fit the exceptions to what products can be offered to what people," he said. "It's not as simple as just migrate people to one system."