I can only guess, but I assume that my readers sometimes reflect on their achievements, and within the bounds of modesty assume they have contributed, however mildly, to the societies in which they live. Frontiers of science, alleviation of suffering, careful driving, scrupulous payment of invoices: that sort of thing. Of course, such self-assessments are often delusional. Memory can be selective, and the occasional important publication shines in recollection, while the large pile of unfinished projects, disgruntled colleagues and abortive grand designs fade into oblivion. Pereunt et imputantur.
What if we were to take an objective measure? Track a thousand newborns, and keep a close account of the profit and loss ledger. At this point you may feel a trifle uneasy. Who are we to judge these matters? What price the jocular remark of a mute inglorious Milton? How could one possibly assess the wit of someone who lacks a Twitter account? Furthermore, you may recoil at the possible results of such an enquiry. If some individuals turn out to be a nuisance and a high cost to society, what then? Should they be exiled to some other land whether the natives are even more generous and gullible, or should we intervene as best we can to make them into productive citizens? These are not trivial matters, and the researchers were at pains to highlight the moral choices which arise from a clear headed evaluation of costs and benefits. In particular, their discussion pre-supposes a compassionate society, with redistributive taxation providing educational, health and welfare benefits. The question barely arises outside a welfare states. In such less kindly states, if people are a nuisance they are simply a nuisance, but not a direct cost, since no one will be paying them any benefits.
Terrie E. Moffitt & Avshalom Caspi used the ISIR 2014 conference to test reactions from assembled researchers about the findings so far, and about the issues which arise from them. They presented their data on the Dunedin study, a four-decade longitudinal study of a birth cohort of 1000 New Zealanders. They examined risk factors in childhood and measures of social, health, and economic costs in adulthood.
Adult social and economic outcomes fit the Pareto principle: 20% of the cohort accounted for approximately 80% of every outcome: the cohort’s months of social welfare benefits, years of absent-father childrearing, pack-years of cigarette smoking, hospital admissions, pharmacy prescription fills, criminal court convictions, and injury-related insurance claims. Moreover, high-cost individuals with one problem outcome tended to also have multiple problem outcomes. An ultra-high-cost sub-segment of the cohort was identified who accounted for 80% of multiple problems.
I can remember my interest in the Pareto principle when I first came across it, but I now see it as part of what I call “the comparative percentages muddle”. For example, would you be outraged to hear that 90% of national acne is owned by 10% of the population? A moment’s thought will show you that some people have acne and others do not. Comparative percentage obscures a skewed distribution. Teenagers tend to have acne, and some young adults have acne which reaches chronic levels. Then take the more usual diatribe: the top 1% own 10% or 30% or whatever of the national wealth. In the same way that it seemed odd that some some small percentage “own” all the acne it seem iniquitous that another small percentage owns a large percentage of the wealth. The comparative percentage muddle is based on the untested assumption that 1% of the population should own no more than 1% of the wealth. Comparative percentage shares are a clumsy (and perhaps intentionally misleading) way of showing distributions. For example, in a country where every citizen is paid the same wage for 40 years it will still be the case that older workers will have more savings than the young because they will have had more years in which to build up savings, even in a country where you cannot pass on your wealth to your children. Savings accumulate over the life course, so without age correction the comparative percentage wealth statistic is misleading. Add in compound interest on savings, and add in a mild wage differential for more educated workers and the whole thing becomes a muddle in search of indignation.
The authors know all this, and realise that the beguiling Pareto observation is a post-hoc description, which of itself predicts nothing. In this case it simply asserts: there are some troublesome people, and they will account for most social problems. The critical question is: which kids will grow up to be responsible for a disproportionate amount of trouble (and can anything be done to make them behave better)?
The authors say: Risk factors measured in childhood that characterized this ultra-high-cost group were: low family socio-economic status, child maltreatment, low self-control, and low IQ. Effect sizes were very large. Predictive analyses showed that together, SES, maltreatment, self-control, and IQ measured in the first decade of life were able to predict 80% of the individuals who are using 80% of multiple costly services. We developed an index of the integrity of a child’s brain at age three years. This age-3 brain-integrity index was a strong predictor of the cohort members who four decades later became members of the ultra-high-cost population segment.
Implications: Much research has shown that childhood risk ‘X’ can predict poor adult outcome ‘Y’, but modest effect sizes discourage translation of findings into targeted childhood interventions. This study illustrates that the vast bulk of a nation’s social services, crime control, and health-care are expended on a relatively small population segment. During early childhood, this population segment is characterized by a small set of risk factors: low SES, child maltreatment, low self-control, low IQ, and poor brain integrity. Reducing these factors may bring surprisingly good return on investment.
The comments from the audience were that it would be an error to describe the neurological examination as an “index of the integrity of the child’s brain”. Brains are assumed to be present. Better to say that an examination of behaviour, skills and neurological responses shows that many of the troublesome children can be detected at that age.
The assessment is interesting. It includes the Peabody Picture Vocabulary Test, which is simple and a good predictor. A word is spoken and the child has only to point to the one of four pictures which best describes the word. It has been doing good work since 1959 and is an excellent example of the power of intelligence measures: simple to do but profound in their implications. They also tested language and motor development, and simplest of all, what the child’s behaviour had been like during the 90 minute session.
There were varying views as to whether interventions in early childhood would be effective. I think the Abecedarian project achieved useful results in increasing ability somewhat (by about 4 IQ points on average), but not all researchers are convinced about that. Training parents in how to manage a very difficult and demanding child could be very useful, but that remains to be proved at the scale required, though King’s College has done good pioneering work on this.
The core of the argument is a social one, and goes to the heart of policy making. The authors calculate that about 45% of the population are “low cost users”. In other words, they draw very little on community resources, yet pay most of the taxes that provide those services to others. The authors have identified some ultra high cost users who are a net drain on resources. Compassionate societies pay their bills, including the highest bill, which is often being the target of their bad behaviours. Whilst they remain willing to do so welfare states will survive, and might even invest yet more resources in the hope of bringing about improvements in parenting. If they were to decide to invest all of their resources in their own children rather than divert their earnings to other people’s children the redistributive State would collapse.