The phrase "are strictly based" is correct and usable in written English.
It can be used when emphasizing that something is founded or grounded on specific principles or criteria without deviation.
Example: "The conclusions of the study are strictly based on the data collected during the experiment."
Alternatives: "are firmly grounded" or "are solely founded".
These fellowships are extremely generous and particularly difficult to obtain, because they are strictly based on an international competition.
The analyses are strictly based on numerical experiments and the ideas here presented are intended to encourage researchers in the optimization community to explore LR dualization in other practical and relevant problems.
There, however, nomads and refugees are from different and rather antagonistic ethnic groups; the former are Turkana and the latter mainly Dinka, so that the relations between them are strictly based on trade.
Variations in experimental results and opinions are strictly based on the design and method of experiment adopted, coupled with size and scale effects arising from the nature of material tested.
Scholarships that are strictly based on academic merit may also ask for a high school transcript showing your GPA as well as a copy of your score report from the ACT or SAT.
The scenario-based methodology is strictly based on observable facts and data and complemented by physical modelling techniques, which can be submitted to a formalised validation process.
It's strictly based on performance.
Although it pitches group against group, it is strictly based on the idea of selfish genes.
Mr. Tunney said his departure had nothing to do with the dispute and that his hamburger startup was strictly based on a lifelong passion.
At first, they were strictly based on social hierarchy, but after World War II and the democratization of Japanese society, they began to be used according to the level of intimacy between speakers.
"Our reason for the refusal is strictly based on Mr. Zielbauer's adamant and -- I'm trying to think of the right adjective that I want to use -- refusal to provide letters of reference," he told the board.
