And so, airspeed is often used as an indirect indicator of approaching stall conditions.

"Most of the data pointing to recovery are soft, peripheral or indirect" indicators, he said.

Waist circumference is an indirect indicator of intraabdominal fat tissue, often called visceral fat.

In addition, it looked for evidence of disease like heart attacks and cancer rather than indirect indicators like cholesterol levels, which can be misleading.

The goal, he said, is to try to get an exercise dose-response curve, at least for these indirect indicators of benefit.

These markers can be good indirect indicator of NM but most are not sensitive enough to improve cytogical diagnosis.

Researchers have often relied on indirect indicators, like shrinking numbers of insect-loving birds, but there are other possible explanations for their loss.

One idea might be to use so-called surrogate markers, indirect indicators that aging is slowed.

But indirect indicators give a glimpse of the troubles.

GDP is the most effective instrument for measuring macro-economic activity, while also serving as an indirect indicator of social development and progress.