Making A Math Murderer

Just think of all the questions that arise when a seemingly-healthy baby dies. Was there an illness that went undetected? Was there a rare genetic defect that couldn’t possibly have been known? Are any signs of physical trauma related to the resuscitation efforts of a fragile infant, or something more sinister? Every time a baby dies, police investigate with a host of complex questions to determine whether the death is natural and accidental, or… not. And the odds are anything but clear.

So what do we do when it happens twice to the same person? What are the odds of THAT?

A British mother named Sally Clark suffered two separate tragedies with the deaths of her infant sons. Her resulting trial for murder included expert testimony from Sir Roy Meadow, a noted expert on child abuse cases. And Meadow’s misuse of conditional probability painted Sally Clark as perpetrator rather than a victim.

Math is often theoretical, but sometimes doing it right is the difference between life and death.


Ben-Israel, Adi. “Using Statistical Evidence in Courts: What Went Wrong in the Case of Sally Clark?”

Dyer, Clare. “Falsely Convicted Sally Clarke Dies Suddenly.” BMJ: British Medical Journal, vol. 334, no. 7594, BMJ, 2007, pp. 602–03,

General Medical Council v. Meadow, England and Wales Court of Appeals (Civil Division),

Nobles, Richard, and David Schiff. “A Story of Miscarriage: Law in the Media.” Journal of Law and Society, vol. 31, no. 2, [Cardiff University, Wiley], 2004, pp. 221–44,

Scheurer, Vincent. “Convicted on Statistics?”

Schneps, L., & Colmez, C. (2013). Math on trial: How numbers get used and abused in the courtroom.

Watkins SJ. Conviction by mathematical error? Doctors and lawyers should get probability theory right. BMJ. 2000;320(7226):2-3.

Webster, Richard. “Roy Meadow and the Statistics of Cot Deaths.”

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