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Tag Archives: probability

There is a troubling misunderstanding at the core of the current health controversy. The screening tests do not give a diagnosis of cancer or an “all clear”; they deal in probability and risk.

A couple of days ago the then Head of the HSE, Tony O’Brien, explicitly said so before a Dáil committee. His interlocutor failed to explore it and went off on a rant, treating what had been said with dismissive contempt, as an excuse or possibly a lie. T.O’B. accused him of trying to spread a public panic.

T.O’B. resigned yesterday when the contents of a memo he received in 2016 were revealed. The memo is complex but has that same core: the tests do not deliver diagnoses. Moreover, it pointed out that if patients went to the media and journalists chose to run headlines and stories to the effect that “screening did not diagnose my cancer”, there would be public panic.

Now the worst kind of politician and journalist would be prepared knowingly to propagate and exploit a panic. The more likely problem is, however, far more serious in the long term. Presumption of innocence towards elected representatives and journalists suggests that they too are subject to the panic because they fail to understand or grasp the significance of what T.O’B. said at the Committee. They don’t get the test-marker/diagnosis distinction. Indeed they don’t get risk, probability and live in a binary world of certainty; in this instance that’s simply cancerous or all-clear and anything else is a failure of government to mind us.

This level of misunderstanding among citizens is a dreadful comment on Irish education but it is utterly unacceptable in a member of parliament or a journalist. It not only makes public discourse next to impossible but almost certainly makes health screening initiatives for the future at best something for the wary and at worst unlikely to be implemented.