"demonstrated ability to" is a correct and usable phrase in written English.
You can use it to refer to someone's capability or capacity to do something. For example, "He has demonstrated ability to effectively manage a team."
In his 18 years with G.E., Mr. McNerney certainly demonstrated ability to deal with change.
And you are too quick to discount the industry's demonstrated ability to use technology to protect the environment.
There's a lack of infrastructure and insufficient demonstrated ability to clean up in the Arctic.
"Many managers have a demonstrated ability to be tactical," Mr. Pinto said.
"These parents have a demonstrated ability to meet their financial responsibilities to their children, but have consistently refused to provide the support they owe," Mr. Thompson said.
Mr. Welch said, "Clayton, Dubilier & Rice's demonstrated ability to deal with significant operating challenges and to focus on creating better businesses plays to my interests".
His demonstrated ability to woo independents, even Reagan Democrats, in key battleground states like Ohio, Pennsylvania and Florida makes him a huge potential asset.
That North Korea has sought to acquire H-bomb technology is beyond doubt, as is its frequently demonstrated ability to exert a form of international blackmail.
And the measure of that greatness is not the capacity to destroy, it is your demonstrated ability to build and create.
"We have a demonstrated ability to simultaneously mobilize our base and also attract the support of ticket splitters and swing voters, so we can reach across that divide a little bit.
"And the measure of that greatness is not the capacity to destroy, it is your demonstrated ability to build and create," he added, alluding to Iran's contested nuclear program and its missile development efforts.
