1. Lots of jobs are short-lived. Even in good times, one job in seven is destroyed every year. Over a quarter of low-paid jobs last less than a year. And one study found that 42% of new jobs last less than 12 months. This means that many of those who do move will find themselves out of work shortly afterwards.
2. And they’ll be a long way from their friends as well. This matters, because large social networks help people back into work - as they learn of job openings from friends. In this sense, IDS’s proposal might not reduce unemployment much overall, as it’ll increase the duration of unemployment for those who move house and then lose their jobs.
3. Moving away from one’s friends reduces happiness. Nattavudh Powdthavee has quantified this (pdf). He’s calculated that the difference in happiness between a person who sees their friends and relatives less than once a month and one who sees them most days is roughly as great as the difference in happiness between the unemployed and those in work.
This means that, for the average unemployed person, moving into work and losing close social networks is neutral for happiness. In this sense, IDS’s idea fails to promote the general well-being which David Cameron has advocated - and is certainly inferior to job creation in areas of high unemployment.
I’ll concede, though, that there’s a selection effect here. If IDS offers only genuine incentives for the unemployed to move, then those who take up the offer will be those who value working highly and friends (if they have them) lowly, so aggregate happiness will increase.
This, however, assumes that IDS is true to his word and offers only carrots rather than threats, and that people are good predictors of their own well-being. Both assumptions are doubtful.
4. If large numbers of people move into areas where there is work, there will be “pressure on public services” and a potential erosion of social capital. But these are exactly the objections some people have to immigration. Quite how one can oppose immigration and favour IDS’s proposal is unclear - unless, that is, you‘re a racist.
There is, though, one effect of his idea. Insofar as people move from areas of high unemployment to low unemployment, rents and house prices will rise in the latter. I suspect, then, that IDS is pursuing pure Thatcherism - he wants to increase house prices in Tory-supporting areas.