Probability, Child Abuse and Munchausen Syndrome

“In a single family, one sudden infant death is a tragedy, two is suspicious and three is murder, until proved otherwise”.

–   Sir Samuel Roy Meadow in his book ABC of Child Abuse.

Baron Munchausen was German nobleman who joined Russian Army and fought against Turks. When he retired, he loved to tell stories of his Russian adventure during dinner parties. Most of stories were highly exaggerated/unbelievable.

Later a medical disorder was named after him- Munchausen Syndrome- wherein a person suffering from this syndrome feigns illness just to attract attention or gain sympathy. Such people will repeatedly get themselves tested, get admitted in hospitals, take medicines for diseases they don’t have, in return they seek attention/sympathy from others.

British paediatrician Roy Meadow identified disorder among mothers of newly born/young children. Some mothers abused or harmed (in worst cases even killed) their child just to gain attention or sympathy. Roy Meadow called this as Munchausen Syndrome by Proxy. Here some else (i.e. child) is abused so that abuser gets attention.

Poor Baron, who was master story teller, got his name linked to mental disorders and child abuse.

But story does not stop here.

In 1999, a British solicitor called Sally Clark was convicted for murder of her two baby sons. Her first son died in 1996 when he was few weeks old, the reason for death was sudden infant death syndrome (SIDS). In 1998 she gave birth to another son, he too died within weeks under similar circumstances. In both cases Sally was only person present with child during death. Sally was arrested for murder of her children.

Roy Meadow was called as expert witness in this case. Roy went through the statistics of SIDS and predicted that in case of non-smoking, affluent family (category to which Sally belonged) probability of SIDS is one in 8543. Since birth of child is independent event, probability of two consecutive deaths due to SIDS in such family is 1/8543 x 1/8543 = 1/ 72982849 i.e. nearly 1 in 7 crores, so since two SIDS in a family is such a rare event, it was likely that Sally had killed her children, so was declared guilty. But Sally Clark was not alone, Roy Meadow appeared as witness in three more similar cases (Donna Anthony, Angela Cannings and Trupti Patel), and in each case the accused woman was declared guilty of infanticide.

Royal Statistical Society declared that Roy Meadow’s calculation of probability was invalid and such probability should not be used for declaring someone guilty.

Royal Statistical Society questioned Roy Meadow’s assumption that two SIDS in family are independent events, in fact due to genetical factors, in a particular family, chances of second child dying due to SIDS after first child’s death due to SIDS is much higher compared to some other family.

Secondly, 1 in 7 crores were chances of having two cases of SIDS in a family, which was wrongly attributed to innocence of Sally i.e so it cannot be said that chances of Sally being innocent were 1 in 7 crores.

Question in this case should have been -“Were such deaths natural or deliberate?”- Compare probability of death of two infants in family due to natural causes with probability of mother killing her first two children. Calculated thus it was found that in only 1/3 cases deaths were due to foul play, in other cases it was due to natural causes or genuine SIDS. So chances of Sally being innocent were 2 in 3. Later investigation found out that her second child died due to bacterial infection and not due to SIDS.

Anyway, since statistics were not relevant for this case,  higher court reversed the order and Sally was set free. This judgement also resulted in Donna, Angela and Trupti being set free.

The story does not end here, in fact it has tragic ending. After being released from prison, Sally suffered from depression and died due to alcoholism.