Thursday, 14 January 2016

Jonathan Portes replies to Adam Perkins


Adam Perkins has now admitted that his claim "the higher the proportion of unemployed adults in a household, the greater the number of children - on average - that it contains" is true only if you exclude households that do not have any children.

This is, I am afraid, not how you calculate an average. It is roughly equivalent to saying that Manchester City would have scored more goals than Arsenal per match this year if you don't count the matches where they failed to score any at all. He also justifies this by claiming: "the government dataset from which it is taken states that households refers to those where at least one occupant is aged 16-64 and at least one occupant is aged 0-15.". This is flatly untrue, as anyone with the remotest familiarity with household data knows.

The source data is here: …. "

Looking at the link, to my eye the relevant description is: "Out of the 20.7 million households (where at least one member is aged 16 to 64), in April to June 2015, in the UK, 11.6 million (55.9%) were classed as working, a further 5.9 million (28.3%) were classed as mixed, and 3.3 million (15.8%) were classed as workless." In other words, the extra requirement which Adam Perkins states “and at least on occupant is aged 0-15” is not referred to in these data.

Jonathan Portes concludes:

As the ONS clearly states, this data covers all households, with or without children, where at least one occupant is aged 16-64.


  1. Portes seems to be arguing against knowledge. If one broad category of Britons sharply bifurcates into
    (1) the most fecund members of the population, and (2) the least fecund members of the population, why is he so concerned to avoid knowing more about the distinctive characteristics of the two groups of people? Doesn’t he understand that, over time, the children of the most fecund will come to outnumber the non-children of the least.

    The football metaphor is somewhat strained. But think of it this way. If you were the manager of Arsenal, you’d monitor the individual performance averages of every member of your team. If you’re winning matches purely because you have two players who are the best goal scorers in the country, while all your other players are rubbish, you’d be worried. You’d be even more worried if all the younger players coming along were more like your nine rubbish players than your two great ones.

  2. The question here is surely about the division between the extensive (whether to have children) and intensive (how many children to have) margins. Dr Perkins' analysis assumes that there's a significant division here, so that only those choosing to have children should be considered. Mr Portes' view is that all people are making a choice over how many children to have.

    Mr Portes' football analogy works *if* you assume that all people want to have children and are just wondering as to how many. But we all know people who consciously choose not to have children. They would be like football teams intentionally not scoring any goals in certain matches. The issue here is observing whether, having scored no goals in a particular match, it was because the team performed poorly or had decided not to score any goals.

  3. The underlying assumptions about “worklessness” that underpin Perkins’ “research” were comprehensively debunked and refuted by the Joseph Rowntree Foundation back in 2012:

    Perkins’ work is the stuff of ideologically -motivated and manufactured policy-based “evidence” - rather than what is required – namely, evidence-based research with which to inform sound, and humane, public health and social policy.

  4. Thanks. Have you a link to the original publication, and some guidance as to which parts of it refute the arguments put forward in the book?