"This seems so far from what people would take as strong scientific evidence or a direct causal link," he said.

But the researchers said a causal link was not proved, and urged more research.

"There is a causal link between funding and educational opportunity."

The reports do not prove a causal link between the drink and any health problems.

This assumes that there is a causal link between information and human behavior.

For that reason, he said, "it doesn't provide a causal link."

There is a strong causal link, they claim, between money and prices.

But, unless we look deeper into the causal links, these can be misleading.

If this causal link is not present the application will fail.

The causal links however are by no means clear.