No one would doubt that 'family breakdown' can be costly, not least to the people directly involved.
Attempting to put a number on that cost seems more popular a task than ever. Outgoing chief Rabbi Lord Sacks - who criticised the government this morning for failing to do enough to encourage marriage - cited one such estimate:
"The state has an interest in marriage because the cost of family breakdown and non-marriage, the last time I looked at it, was estimated at £9bn a year."
While the Chief Rabbi's office hasn't yet confirmed his source, if it is the same figure, it isn't accurate to claim that it's the cost of family breakdown. As we've seen before, the 120,000 'problem' families are those with facing multiple difficulties, including low incomes, mental health problems or disability, but can include both single- and two-parent families.
However there have been a number of other figures put forward, and as estimates of 'family breakdown' go, Lord Sacks' is a conservative one.
"impossible to quantify with any accuracy"
Not our words, but those of the Centre for Social Justice (CSJ) back in 2006, when they referred to the attempt to put a cost on family breakdown. They nevertheless did so, basing their numbers on a Family Matters study in 2000 (£). It mainly looked at the additional income support paid to single parents compared to couple parents.
The CSJ took that, added in new tax credits and inflated the numbers to apply to 2006. The result: a £20-£24 billion cost.
"an inexact science"
So the caveat became by 2009, when the Relationships Foundation also made the attempt to put a number on family failure. This was put at £37 billion, and since then has become £46 billion (with the same assumptions based on updated cost estimates, and some new areas factored in).
Here, family breakdown still centres on the consequences of single parents and divorce but goes some way beyond benefits and tax credits. It also factors in Housing and Council Tax Benefit, NHS costs and the cost of prescriptions, policing, prisons, legal aid and even young people not in education, employment or training (NEETs).
In most cases, it's bascially a matter of estimating the proportion of money the government is already spending in a given area that can be attributed to lone parents compared to the equivalent costs that couple parents might impose. In some areas there are exact estimates (Housing Benefit caseloads being one example). In others (such as the costs of GP visits) it appears to be left to an approximation with no further explanation given.
"complex and difficult to calculate"
So said the authors of a research paper in 2011 which put the cost higher still, at at least £100 billion. All the previous estimates, as 'inexact' and 'impossible' they may seem, factor in only the direct costs attributable to being a single parent, a child in care or a victim of domestic violence.
This study tried to factor in the indirect costs - such as the human and emotional costs of domestic violence, estimated in a 2004 study at £17,085,570,000. Estimates like these were based, in part, on using surveys from road traffic accident victims which asked what people would be willing to pay for a reduced risk of having such an accident (the so-called 'willingness-to-pay' approach). So much so they even put the cost of an indivdual death at £750,640.
Complex and difficult to calculate doesn't even begin to do justice to the caveats that must be applied to these indirect cost estimates - its open to question just how useful methods which start at road traffic surveys and become £17 billion in human and emotional costs of domestic violence really are.
Researchers who want to quantify family breakdown are hence left in an impossible position - include indirect costs and they'll almost certainly be wrong, or exclude them and be left with a limited estimate that doesn't capture the whole issue. Either way, nobody knows the true financial cost of family breakdown and nobody is likely to. Any estimate that purports to should be treated accordingly.