The phrase "materially improved" is correct and can be used in written English.
You can use it when you want to say that a situation or thing has been distinctly improved or made better in a significant way. For example, "We have seen a materially improved result this month than last month."
As evidenced by improvement in both AUC and net reclassification index, RDW materially improved the prediction of mortality over and above traditional severity of illness, as measured with SAPS.
Still, they materially improved the lives of ordinary workers.
Technology has given doctors many more tools, and has materially improved patients' lives.
The economy is terrible, the job situation has not materially improved, and illegal immigration and national security will get even worse moving forward.
Quitting smoking then would not have materially improved his patient's prognosis but probably would have added additional stresses during an already difficult period.
In other words, the market pricing is increasingly priced for a stronger economy over the medium term, even as Labor's chances of winning the election have materially improved.
It's not that the Morrisons' circumstances materially improve.
"I don't think these larger applicant pools are materially improving the quality of their classes.
In the meeting, Secretary of State John Kerry argued that lifting these sanctions would not materially improve Iran's economic plight.
"There is no evidence that an increase in the coverage level would promote competition or materially improve the ability of community banks to obtain funds.
However, we retain our buy rating as we believe Vodafone has attractive potential to materially improve its structural position by acquiring cable assets, and realizing substantial potential synergies.
