"margin to improve" is correct and usable in written English.
You can use it when referring to a margin which could result in an improvement in something, such as performance or attitude. For example, "The team has a lot of potential, so with some effort they may be able to create a margin to improve their success."
Linear Fresnel collectors still present a large margin to improve efficiency.
Results show that the uncertainty analysis methods can provide larger reactor design criteria margin to improve the economy of reactor.
By allowing timing errors to occur and recovering them on-line, resilient systems are designed to eliminate the design margin to improve performance or reduce power.
So the idea is, what you do at the margin to improve your profits as a capitalist, leads to the declining rate of profit in the industry as a whole, because as we become more and more capital intensive in the production of cotton we have less and less living human labor-power going into the production of cotton, and it's only living human labor-power that produces fresh value.
We have a lot of margin to improve.
"We were just concentrating on working on the race set-up and we still have plenty of margin to improve.
The company has said it expects its profit margins to improve by emphasizing software.
The financial task force had four goals: to increase operating margins, to improve asset management, to raise productivity, and to grow revenues.
My community would just like to see us not strangle what we have already created and work at the margins to improve what we have.
We forecast earnings before interest and tax margins to improve to 6.0% by 2017 and 6.9% by 2019, and we expect Royal Mail to be able to deliver 8.7% EBITDA and 16% earnings growth over 2014-2017.
As the Bank's monetary policy committee has cut rates from 5% in October in several stages, banks have tried to widen their lending margins to improve their battered balance sheets.
