[...] there is both continuity and change in people's circumstances from year to year. We do not live in a country where there is an annual lottery to determine at random who is rich and who is poor for the coming year regardless of where they started last year. But nor do people generally stay stuck in the same place. Those who start poor are more likely to stay poor the next year than those who do not, and those who start rich more likely to stay rich. But many in each group--and those in between--move up or down the income ladder each year.

[...] Today, social housing--rented out at below market rates by councils and not-for-profit housing associations--is in many people's minds synonymous with housing people with low incomes. But it was not always like that--back in 1979, more than 30 per cent of people with incomes in the top half of the income distribution lived in social housing. By 2004, it was less than 10 per cent. Between those years, the supply of social housing available to let to new tenants each year dwindled--fewer new houses were built; property was sold off through the 'Right to buy', so that when occupants moved or died it was not available as social housing, and fewer tenants moved out of social housing or died.

• they can act as disincentive to additional earnings;
• they can give an incentive to behaviour that reduces reported income (including misreporting of circumstances to slip below particular thresholds);
• they can lead to feelings of injustice, if those just below a threshold are treated much more favourably than those who are only slightly better off;
• uncertainty about which side of a threshold someone will fall once all the calculations are done can add to barriers to access.