dont buy computer but if you do

Don't buy a computer, but if you do

Over at India Uncut, Amit Varma points to study by Todd Kendall which

claims to demonstrate that the spread of the internet causes a decline

in the incidence of rape. Kendall's argument is that the Internet

makes pornography more widely available, especially to men in the

15-19 age group, and serves as a substitute for sexual violence.

It's an interesting paper, but reading it I had several concerns.

My biggest problem with Kendall's empirical results is that he runs a

regression with both % of households accessing the Internet and % of

households with computers as independent variables, and while the sign

for Internet access is significant and negative, the sign for

households with computers is significant and positive (it's the most

significant variable in his regression) - a fact that Kendall

conveniently neglects to mention in his paper, let alone provide an

explanation for. Kendall's justification for including % of households

is to seperate the effect of the Internet from other technological

influences, but that would imply a non-significant effect of owning

computers but a significant effect of Internet access. As it is, we

have two variables in the right hand side of the equation that we

would expect to be highly correlated (Kendall does not bother to

provide us with a correlation table, but computer ownership and

internet access pretty much have to be positively correlated) and they

enter the regression with signs that are opposite and significant.

Personally, I'd love to see what happens to the coefficient on

Internet access if Kendall runs his regression without % of households

with computers in there. I'm unconvinced that it would continue to be

significant.

Think about it this way. Kendall tells us that, on an average, a 10%

increase in Internet penetration causes a 7.3% decline in incidence of

rape [1]. But if you believe his results in Table 4, a 10% increase in

the % of households owning a computer causes a 6.4% increase in the

incidence of rape. So the net effect of buying a computer and using it

to access the Internet on the incidence of rape is a mere 0.9% (yes,

yes, I know it doesn't work that way - which is exactly my point). But

who are all these households who are buying a computer but not using

it to connect to the Net? And what, according to Kendall, is the

reason that they're more likely to commit rape? Frustration about poor

connectivity? Isn't it more likely that what we're seeing is just

multicollinearity unrealistically inflating the regression estimates?

My second concern with Kendall's study is that he assumes implicitly

that the spread of the Internet has no effect on the reporting of

rape, so that changes in the number of rapes reported is a valid

measure for number of rapes actually taking place. Kendall

acknowledges that there is a measurement problem here, but sees no

reason to believe that the spread of the Internet may be causing a

systematic bias in his measurement. He even makes some arguments for

why his measures may be underestimating the effect.

Yet the study itself suggests one potential reason why the results

might be biased. Kendall tells us that rapes that don't get reported

tend to be those committed by people known to the victim - date rapes,

for instance. Kendall also cites previous literature that tells us

that the Internet facilitates more dating and other face-to-face

interactions and that this may increase the opportunities for rape.

Put those two together and it suggests that the spread of the Internet

increases the opportunities for the kind of rapes that tend to go

unreported. Is it possible, therefore, that the effect Kendall is

capturing is really a reflection of the fact that the Internet is

shifting the incidence of rape from assaults on strangers (which have

high reporting rates) to date rape (where reporting rates are low),

causing reporting rates to go down? I'm not saying this is necessarily

happening - I'm simply saying that it's an interpretation of Kendall's

results (such as they are) that would be consistent with the

literature that Kendall himself cites, and that he doesn't consider.

Finally, it's interesting that though Kendall has a panel data set, he

doesn't actually account for lagged effects in his model. So what

we're seeing is the absolute level of rape in the state (and the

absolute level of internet usage) not the change in rape incidence.

Personally, I would love to see a regression where Kendall includes

the previous year's rape incidence for the state on the right hand

side or, even better, takes first differences for his variables of

interest. That would tell us whether changes in the spread of the

Internet were really driving changes in the incidence of rape.

None of this is to say that what Kendall is saying is necessarily

wrong, though personally I'm sceptical about the argument that access

to porn is a substitute for rape (in Kendall's terms, I'm firmly in

the camp of those who believe that rape is about power rather than

about lust). It's simply to suggest that Kendall's results and the

interpretation he puts on them are extremely questionable, and we

should be careful before drawing any real conclusions from them.