The court made heavy use of statistical calculations to achieve its conviction. In a 2003 TV special of "NOVA", Dutch professor of Criminal Law Theo de Roos stated: "In the Lucia de B. case statistical evidence has been of enormous importance. I do not see how one could have come to a conviction without it". The law psychologist Henk Elffers, who was used by the courts as expert witness on statistics both in the original case and on appeal, was also interviewed on the programme and stated that the chance of a nurse working at the three hospitals being present at the scene of so many unexplained deaths and resuscitations is one in 342 million.