The uncertainty is also not good for the rest of the United Kingdom, he added, which has seen stellar economic data and has been applauded for being one of the fastest growing G-7 countries since the global financial crash.
It's also not good for the European Union, according to Rogoff, with the possibility of Scotland now joining the bloc meaning that other autonomous communities - like Catalonia in Spain - might also look for their own referendums on independence.
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"Other places in Europe (will) say, 'Hey, we can do that too'," Rogoff said. "So it's certainly quite a wild card there."
Swing in polls
A survey by British research company TNS on Tuesday showed that 38 percent of Scots back independence compared to 39 percent who are opposed. The same poll a month ago had 32 percent in favor of independence and 45 percent opposed.
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With early indications appearing to show the vote is on a knife edge the leaders from the three main political parties - including Prime Minister David Cameron - have opted to miss their weekly debate in Westminster to travel north of the border. They will campaign on behalf of the "no" vote in a last-ditch attempt to effectively save the Union.
At the same time, pro-Unionists are thrashing out a plan to give Scotland more powers if voters reject independence. Sterling has sold off sharply on the uncertainty in recent trading sessions and U.K. banks and Scottish-based firms have also seen a dip in stock prices.