The phrase "are chiefly based" is correct and usable in written English.
It can be used when discussing the primary foundations or sources of something, such as theories, ideas, or research.
Example: "The conclusions of the study are chiefly based on the data collected over the past five years."
Alternatives: "are primarily founded" or "are mainly derived".
The approaches to privacy protection in data storage phase are chiefly based on encryption procedures.
While the criteria for natural selection in biology are chiefly based upon physical fitness and reproductive capability, in music these criteria will depend on the effects of the new rules on the music-making experience.
Extant accounts of the storms in 1850 are chiefly based on private weather records and press reports, and only approximate storm tracks are known.
Sentinel networks in Europe are chiefly based on general practices (and in some European countries also on paediatric primary care services) and these are essential to provide insight into what is happening in the community at large.
Current recommendations to initiate dopaminergic therapy in early PD with a DA, or even a monoamine oxidase inhibitor, are chiefly based on concerns about the evolution of motor complications characteristic of sustained LD therapy, most notably drug-induced dyskinesias.
Var?, born in Paris in 1883, received his earliest training in France but was chiefly based in the United States from 1915 until his death in 1965.
The information presented here is chiefly based on the returns made by 140 countries to the Social Security Administration of the United States and published in 1985 as Social Security Programs Throughout the World.
The creators of the "American Psycho" musical, which is chiefly based on the 1991 satiric thriller by Bret Easton Ellis, are having a workshop this week, with plans to hold a private presentation for theater producers and artists on Friday, according to two theater executives familiar with the workshop and planning to attend the presentation.
The methodology of this paper is chiefly based on Laffont and Rochet (1985).
The developed lab-scale solar reactor basically pertaining to the indirect heating concept is chiefly based on a tube-type configuration in tandem with a cavity receiver.
EAF is considered a progressive benign disorder, and the diagnosis is chiefly based on histopathological findings [1] more specifically the presence of an inflammatory infiltrate with numerous eosinophils and fibro-inflammatory lesions.
