The phrase "an increase in the frequency and" is correct and usable in written English.
It can be used when discussing a rise in the occurrence of something, typically in a scientific, statistical, or analytical context.
Example: "The study revealed an increase in the frequency and severity of extreme weather events over the past decade."
Alternatives: "a rise in the occurrence and" or "an uptick in the rate and".
A rash of prominent breaches has brought new attention to an increase in the frequency and sophistication of computer hacking.
"We are seeing an increase in the frequency and intensity of both natural and man-made disasters, meaning that humanitarian organisations are being stretched to respond to more and more emergencies," she says.
"The killing comes amid an increase in the frequency and savagery of crimes committed by young people," thundered the Yomiuri, a right-leaning newspaper.
The link between climate change and an increase in the frequency and intensity of some extreme weather events is becoming ever clearer, and it is the world's poorest and most vulnerable people who are being hit the worst.
Recent trends in settlement agreements, including an increase in the frequency and speed of settlements, which is consistent with concerns raised by institutional investors that some companies may be settling too quickly and without broad consultation.
Already, several hospitals across the country have reported an increase in the frequency and severity of injuries from child abuse.The most recent national data on child welfare available dates from September 2008, before the recession was in full throttle; data from 2009 won't be reported until later this year.
Diffenbaugh anticipates an increase in the frequency of heat spikes.
The inevitable result is an increase in the scale and frequency of abuse of power.
In general, a decrease in respiratory frequency is associated with an increase in the heart period29.
The shift resulted in a dramatic increase in the frequency of drone attacks in Pakistan.
This increase cannot be caused by the increase in the frequency of collisions between colliding molecules, since the frequency does not increase sufficiently with a rise in temperature.
