SHAKY STATISTICS

Re: Marijuana is dangerous, now and in the future, March 12.

I was intrigued by the scientific studies cited in Margret Kopala's
column. Scientists from New Zealand and Sweden concluded, based solely
upon statistics, that cannabis causes psychosis.

Applying similar logic, one would be forced to conclude that tobacco
smoking causes schizophrenia because 80 per cent of schizophrenics
smoke tobacco, according to Ann Crocker, a professor of clinical
pharmacology at Flinders Medical Centre in Australia.

Despite an even stronger statistical correlation, we don't see media
headlines announcing that tobacco causes schizophrenia. You can use
statistics to prove almost anything.

Robert Martin,

Vancouver