"telling measure" is a correct and usable phrase in written English.
You can use it to refer to a numerical indicator or statistic that gives an accurate representation of something. For example, "The unemployment rate is a telling measure of the state of the economy."
DALYs, or disability-adjusted life years, are a particularly telling measure.
(That's a telling measure in itself; the fact that Ms. Norman served as executive director for three chiefs of much different temperaments and backgrounds).
A telling measure involves the commissioners who are frequently the faces and voices of the administration at City Council hearings and town-hall-style forums.
Mr. Bush's use -- twice -- of the word "restore" was a telling measure of his eagerness, after several weeks on the defensive, to put Mr. Gore in a similar position.
It's both an unedifying scenario and a telling measure of the occult power of the programme: Doctor Who's producer receives a strip-search from a fake policeman; the fan takes delivery of a script used by Tom Baker.
Still, in a telling measure of the intensity of the response, a sizable minority of works are by deceased artists and have been donated by their families or estates.
And rather than help investors look beyond earnings to more telling measures of corporate performance, analysts have acted as if earnings were the only indicator worth attending to.
But on more telling measures, growth has slowed.
The assessment will also include more telling measures, like participation rates in feeder high schools or recreational leagues, and the views of administrators and coaches.
Each home in Bentonville was on a smart meter, police were told, to measure and record the exact consumption of electricity and water every hour.
Participants were then connected to a machine they were told would measure their brainwave frequency and shown spreadsheets and formulas.
