There's no doubt that e-cigarettes are better than normal cigarettes. There's also no doubt that e-cigarettes are worse than no cigarettes. However that doesn'

There's no doubt that e-cigarettes are better than normal cigarettes. There's also no doubt that e-cigarettes are worse than no cigarettes. However that doesn't answer the question whether they're an improvement. For that you need to look at what people who use e-cigs would do otherwise. And then it gets really complicated, because you really don't know and can only make estimates. That's why this is a question difficult to answer.