Tom Moultrie’s Sad facts – occasional musings on the abuse of statistics
I was alerted to this statistical horror by a friend who found it on the Guardian’s website; the screengrab above shows the original source cited by the Guardian. Nowhere on oneinnine’s website is evidence marshalled to support their contention.
“In South Africa a woman is more likely to be raped than learn how to read”. Say what?
A micro-nanosecond’s consideration should have you scratching your head in trying to interpret this “fact”.
First, the comparison is invalid. Learning how to read is an event that can occur only once in one’s life (and, typically, at a very young age). It is not, in any meaningful sense, repeatable. It is also not exposure-dependent: it is (with exceedingly rare exceptions) not the case that the longer it takes you to learn how to read, the more likely it becomes that you will. As a counter-example, think of a lightbulb – the longer it has been left on, the more likely it is to burn out. The experience of rape, by contrast, is both repeatable and exposure-dependent. The comparison is then one of apples and pears.
Second, what does it mean to assert “more likely to be raped”? The only sensible context for this statement is an implicit “in her lifetime”. (One could surmise that it might mean “more likely to be raped in the next ten minutes/week/month … but that assertion would be patently ridiculous. So let’s assume that oneinnine did indeed mean “in her lifetime”). But doing so raises a slew of statistical problems of how to measure this. The only women for whom one could empirically calculate the probability would be to evaluate the proportion of women who, at some age when they are deemed no longer to be at the risk of rape, have been raped. You can’t do it for younger women (say, looking at the proportion of 30 year olds who have been raped, because some of women may suffer rape later on in their lives). But if you interrogate the proportion of (say) 80 year olds who have been raped, many of those violations would have occurred a long time in the past – possibly up to 80 years ago – somewhere around 1930. Is the incidence of rape the same now as it was in the past? There is almost certainly a secular (period) trend in the incidence of rape which the statement does not permit. There is also certainly an age effect in the incidence of rape: rape does not affect all women of all ages equally. There may also be a cohort trend in the incidence of rape: think of women aged in their early 20s living in Rwanda in 1994.
To calculate the lifetime risk of being raped in 2010, one would need to make assumptions about future period trends in the incidence of rape; assume an age pattern of the incidence of rape into the future, and accommodate any past, present, or potential future cohort effects. By definition, this requires prognostication, and is inherently unreliable. [An identical phenomenon occurs with the calculation of life expectancies: how many years can a baby born in Swaziland today expect to live before he or she dies? The interpretation is not straightforward, as the assumption that has been made here is that when that child is (say) 10 years old in 2020, he or she will experience the mortality of a 10 year-old in Swaziland in 2010.]
So oneinnine’s assertion is contrived from a melange of unstated assumptions about age, period, and cohort dynamics of sexual violence in South Africa, covering a period of time of roughly two hundred years (the retrospective experiences of women nearing the end of their lives combined with the prospective experience of an infant in 2010). These assumptions should be clearly set out, so that people can verify and validate them.
Third, even if we gave oneinnine the benefit of the doubt that they were able to collect and correctly interpret the data on rape in South Africa, the comparison to women’s literacy is simply ludicrous: A global programme of surveys, the Demographic and Health Surveys, has been conducted using a standardised questionnaire for several decades. The surveys use an extensively tested instrument, and are designed and weighted to be nationally representative. The last such survey done in South Africa was in 1998 and showed that – of women aged 15-49 – 8.2% of African women, 3.9% of Coloured women, 0.9% of Indian women and 0.1% of White women could not read at all. In aggregate, 6.9% of South African women aged 15-49 could not read at all. Differently put, 93.1% of South African women of aged 15-49 HAD learned to read. (Other surveys, for example the 2008 National Income Dynamics Study suggest that literacy has increased since the 1998 survey – they find 3.9% of women aged 15-49 across the country reported not to be able to read at all in their mother tongue).
So oneinnine are suggesting that more than 93% of South African women would be raped in their lifetime. Really? (If one was to be generous, one would note that the incidence of illiteracy would be markedly higher among very old African women, but then we are descending into the age-period-cohort rabbit-hole again). No matter, this number is so outrageously high, it simply cannot be true.
In passing, while acknowledging that reports of rape are notoriously difficult to collect in surveys, the disjuncture between oneinnine’s statistics and those from the 1998 Demographic and Health Survey is astonishing: In answer to the question “Has anyone ever forced you to have sexual intercourse against your will by threatening, holding you down or hurting you in some way?”, 4.5% of South African women aged 15-49 answered in the affirmative (interestingly, the figure was lower for older women than younger women); while only 2.4% answered in the affirmative to the broader question “Has anyone ever persuaded you to have sexual intercourse when you did not want to?”. While I have no doubt that these data almost certainly underestimate the incidence of rape or coerced sexual intercourse, it is hard to see how one gets from answers in the range of less than 5% to an implied incidence of rape of 93%.
The incidence and extent of rape in South Africa is a major, major issue and is a shocking reflection on the country, and its attitudes to women, gender roles, patriarchy and domestic violence. Nothing can be said to condone it or explain it away. However, activists should not demean and undermine the severity of the problem by simply making up numbers and facts to suit their position. It helps no-one, and achieves nothing (and is, if anything, counterproductive).
In time, as Goebbels argued, once the lie has been repeated enough times, people will believe it; take it as axiomatic. Oneinnine gets it wrong; it is used uncritically by a journalist on a reputable paper; which is then cited by other journalists, reports and documentation. It will not be surprising to find this ‘fact’ being used to justify and mobilise support for any number of public, NGO and civil society campaigns into the future. And the error is not socially neutral – it distorts the assessment and evaluation of social priorities and funding. The perpetuation of this analytical and statistical lie and its concomitant social reproduction must be stopped.