The Sunday Express ran a story about 4 million Bulgarians wanting to move to the UK. The problem is that this is over 54% of the Bulgarian population. This would leave Bulgaria almost empty. I had thought that it was the usual non-sensical story where the author was unaware of the population of Bulgaria and had just picked a figure out of thin air, but I looked up the story and he is acutely aware of the population statistics. So why do I still think the story is nonsense?
I think it is wrong because of the sample that the story is based around in biased. A sample size of over 4000 is enough to make a reasonable conclusion, but not a sample of 4000 people living in the worst and most impoverished conditions. If you asked 4000 unemployed people from a deprived part of the UK if they wanted to move to place X to get a job you would get the same and perhaps an even higher response. The poll was actually carried out by BTV and there is no idea of the question, nor any idea about who completed it. So I would expect that it is a telephone or online poll. This is self selecting and not representative. This is going to be a survey of those who want to emigrate and it is not an unbiased sample.
Even if the sampling were correct there is still the problem of reality. As people leave the circumstances and opportunities change. Bulgaria has a strong technological manufacturing sector and also the beginnings of a tourist industry. With people moving there might be a reduction in unemployment and poverty. But the reality is that we just don't know what will happen. What we do know is that this story is scare-mongering and that it does not represent the reality.