The phrase "are frequent across" is correct and usable in written English.
It can be used to indicate that something occurs often in various locations, contexts, or groups.
Example: "These types of errors are frequent across different software applications, highlighting a common issue in coding practices."
Alternatives: "are common throughout" or "occur often in".
Outages are frequent across rural Venezuela, but the lights rarely go out in the capital.
Armed incursions from Darfur are frequent across the porous border, endangering humanitarian convoys on the 11-hour drive from the nearest gravel road.
But death penalty lawyers say such struggles are frequent across the country, as unstable, depressed or manipulative inmates facing execution often exert what little control they have by railing against their lawyers.
Therefore, the use of nicotine by athletes, regardless of its form (e.g. snuff, snus), is frequent across many sports and countries (e.g. [8, 22]).
Some symptoms were frequent across diseases while others were more disease-specific.
Some symptoms were frequent across all diseases, particularly those that were systemic, such as fatigue.
We show that alternative splicing and isoform expression is frequent across developmental stages and tissues, and is comparable in frequency to the variation in whole-transcript expression.
Participants identified diarrhea or "loose stools" as the most common disease from consuming unsafe water, although responses such as vomiting, cold, fever and cough were frequent across all respondent groups and study villages.
Examples of problems and conflicts in the supervisory process for higher degrees are frequent findings across the globe [ 12– 15].
Since the August peace deal, ceasefire violations are frequent, and anyone sneaking across the border could be suspected of joining rebels.
Reports of stress melting away while making the 24-mile car trip across the lake are frequent, productivity has surged, and creative ideas have enhanced strategic plans.
