The office of the Privacy Commissioner for Personal Data has raised a host of questions about the government's plan to randomly test Tai Po students for drugs. We should not be surprised. The queries are basic ones which authorities should have answered before announcing last Thursday that the six-month trial would begin in December. It was obvious at the time that the scheme had not been properly thought through; the commissioner's concerns only confirm the lack of forethought.

Privacy is just one of several issues raised by the trial. The government is rightly worried about drug abuse among our city's youth. There is no evidence from similar programmes overseas, though, that random testing greatly reduces use. Rather, it pushes students into using drugs that are difficult to detect, makes heroes and villains of those who are caught, erodes the trust of schools and teachers and opens a Pandora's box of ways to make tests invalid.