There are so many determinants of employment, unemployment, and labour force participation, that we should be wary of ANY promises made by politicians about jobs, credit for job growth, or blame for job losses.
Mike Moffat has it right here, where he takes on the London Mayor, who made outlandish promises about job growth for the London economy. Mike said similar things about job promises put forward by Tim "Who Dat?" [Mike's euphemism] yesterday.
[T]here is only so much municipal politicians can do to create employment. We give these guys far too much credit when things are going well and far too much blame when they are not. The data tells [sic] a compelling story that the London economy is heavily struggling. It is unfortunate the Mayor has to wear that, given that it almost certainly has nothing to do with him. That being said, no one forced him to make a 10,000 jobs pledge - that was a decision he made on his own.
[Note: Mike was a student in my honours intermediate microtheory course some years ago.]