“Bringing that technology together was a very challenging undertaking,” said David Flueck, Marriott’s senior vice president for global loyalty. The task, which created a loyalty program with more than 110 million members, took nearly two years, he said, and entailed writing some 20 million new lines of computer code. “We ended up bringing over about four billion records from the Starwood technology systems,” Mr. Flueck said. He described the merger as 99.9 percent successful, though he acknowledged that it still left millions of customer records in limbo, some for weeks before they were resolved. “It did take us a couple of weeks to figure out why those records didn’t come over as they should have and solve it,” he said. “The challenge there for us is these are very complex questions to answer.” Get the full story at The New York Times