Legislative efforts are also under way to make completed studies available to the public.

The small number of studies available conferred low power to detect such differences.

It noted that the available studies did not eliminate other possible causes.

Since 1991, the institute's researchers have conducted the most comprehensive international studies available on productivity by industry sector.

The few other available studies also support the passive rather than the driven mode.

But it is designed to help only a particular type of lower back pain, and results are not yet available from controlled, double-blind studies.

Most of currently available studies are based on written texts.

"It may be the best single study available," he said, in terms of methodology.

A 1995 review found that available studies were insufficient to shed much light on the consequences.

The most recent available official study (1995) indicated 18,000 deaths per year are a result of hospital care.