Friday 15 January 2016

Adam Perkins corrects Jonathan Portes


CORRECTION: The ONS weblink from 6th October 2015 which Mr Portes claimed was Dr Perkins’s data source for the numbers of children in working, mixed and workless households is incorrect since The Welfare Trait was printed in September 2015 and was published in November 2015. This timeline makes it impossible for the book to have cited ONS source data from 6th October 2015. The actual source data used by Dr Perkins in The Welfare Trait was published by the ONS on 25th March 2014 and is shown at the ONS weblink below (see dataset ref 002530).

As can be seen at this weblink, line 11 of the Excel spreadsheet states “Households here refer to those where at least one occupant is aged 16-64 and at least one occupant is aged 0-15”. This fact renders incorrect Mr Portes’s allegation that the ONS source data used by Dr Perkins does not contain the information that each household shown contained “at least one occupant is aged 0-15”.


  1. In the perhaps forlorn hope of clearing up some confusion..

    Dr Perkins correctly reports ONS statistics about the number of households containing at least one child under the age of 16 and correctly calculates the average number of such children in these households according to the ONS categorisation of households as Working, Mixed or Workless.

    However, from these data, nothing can be said about whether 'unemployed' people - which is the term used by Dr Perkins - have more children on average than other groups of people. There are both conceptual and data reasons for this.

    Conceptually, the ONS definition of a workless household encompasses all households without anyone working. This does not mean that they are all unemployed in the ordinary sense of not working while being capable of work and available for work. It will also cover for example people who cannot work by reason of disability (whether temporarily or permanently) or who are temporarily out of the labour force because they have stopped work while looking after a young child but have every intention of returning to work when the child is older. This further illustrates that the 'workless' household might not have been workless yesterday or might not be tomorrow. The presence of a child in such a family today neither means that the child was born in a workless household, nor that the child will be brought up in a workless household, let alone born to or brought up by parents who are unemployed. So comparing the average number of children in households in which no one is presently working to the average number of children in households with someone presently working does not provide any information about the relative propensity of unemployed people to have children.

    From the point of view of the data used, it is obvious that the number of children people have cannot be calculated from the number of children presently in their household under the age of 16. A family with children aged 4, 14 and 17 has three children, not two children. Any attempt at estimating whether one group of people is likely to comprise larger families than another group must count all of the children that they have. The ONS data does not allow that comparison. It seems clear that the numbers of children under 16 in households categorised as Working, Mixed and Workless is not a proxy for total children because the distribution of households within these categories differs if all dependent children are counted rather than just those under 16. The picture is further complicated by the fact that not all dependent children live with both birth parents, and of course older children may have left home.

    So even leaving aside the conceptual issue, and presuming a impossible static state in which households could not move between the categories of Working, Mixed and Workless, it is simply not possible to calculate from these data anything about the relative propensity of people in 'workless' households to bear children.

    1. Thanks for your comment. Presumably there is data on completed family size which would be relevant, so long as one had some knowledge about income, years worked etc. Will look at all this again later, but grateful for your comments.


  3. It’s quite Interesting post! Thanks for writing this for us; I’ll share this with my friends too. Karen Kerschmann, LCSW