hh465

More lies, damn lies, and statistics

This is an example of speculative “science” created purely for propaganda purposes:

  1. This is a statistical model and not based on real pregnancy data.
  2. It is not based on validated data about rapes in Tennessee. In fact, the article notes” no recent reliable state-level data on completed vaginal rapes.” Instead, it took national data from a 2016-2017 CDC survey, and then “apportioned” the data according to the FBI Uniform Crime reports percentages. When they do this, they get over 40 thousand rapes in Tennessee for the middle of 2022 through 2023. The key here is that the CDC data has a broader definition of rape than vaginal penetration that could result in pregnancy, and uses some indirect measures (e.g. visits to sexual assault service centers), and includes things like sex while drunk. This is in contrast to the actual TBI data, of a little over 2000 reported rapes per year, or about 2500 if one includes incest and statutory rape. Thus, they overestimate the number of rapes in terms of reported rape by about a factor of 10. They justify this by noting that most rapes are not reported, which is true, but introduces an important level of error.
  3. They also used a cockeyed way of estimating pregnancy rate:

    from the data supplement:

    Rape-related pregnancy (incidence) during abortion ban period = CVR * a * b
    CVR = Completed vaginal rape incidence during abortion ban period (calculated as above)
    a = Lifetime rape-related pregnancy rate, 14.9% (CDC 2016/17)
    b = Ratio of per-rape pregnancy rate to lifetime rape-related pregnancy rate (Holmes et al, 1996)
    Specifically, Holmes et al found a per-rape pregnancy rate of 5% and a lifetime rape-related
    pregnancy rate of 6%; hence we estimate the per-rape:lifetime ratio as 5.0/6.0 = 83%.

There is not really a justification for including the “lifetime rape-related pregnancy rate” in this, but they basically double the pregnancy rate by doing this. It would be more appropriate to just use the per-rape pregnancy rate of 5%.

Now, just as the method they use grossly overestimates the rape incidence, the TBI data underestimates it, since it is true that many rapes are not reported. Nonetheless, this is an unvalidated speculative piece that is meant to overestimate the number of pregnancies for political purposes, in my opinion.

Using the more restrictive numbers of about 4000 rapes in TN over this period, and a 5 percent pregnancy rate, one would get 200 pregnancies. If one assumes that about a third of rapes are reported, then you would get 600 pregnancies.

Thus, the “real” estimate, in my mind would be anywhere between 600 and 5000 pregnancies.


AWA: This was a comment written by hh465 that, I felt, should be promoted to the front page.