There is no systematic evidence of a problem - Frank Field, one of the signatories to the amendments admitted that.

"But now we have systematic evidence on which to base advice."

In Britain no systematic evidence exists of the role of governing bodies in reviewing the curriculum.

However, the news media should not accept and propagate it, relying on anecdotes and assertions despite all of the systematic evidence against it.

Anecdotes do not equal systematic evidence (they're inferior): "while vaccinations may work for millions of people, that will not help little Billy who now has autism."

Conversely, opponents point to the lack of systematic and documented evidence proving that t'ai chi ch'uan is an effective modern martial art.

"Suddenly, with no systematic evidence, we see a lot of old superstitions introduced," he said.

There have been anecdotal reports of depression and suicide in teenage steroid users, but little systematic evidence.

If systematic evidence of discrimination exists, the lawyers would be lining up plaintiffs for lucrative class action cases under existing anti-discrimination laws.

Researchers are beginning to accumulate the systematic, hard evidence that advocates need to make their case.