In theory, one of the goals of general education is to define what is supposed to be common knowledge, and to make it so. But clearly people forget many things they learned at school, and learn many things from media or internet.
Maybe there are some standardized exams where you could look at the results, if they are published in details, to see what students actually learned.
But I suspect that whatever method you use, at the end there will be a scale… some things generally known by 99% of your target population, some known by 90%, 80%, 50%, 20%, 10%, 1%, 0.1% etc.
This kinda feels like a problem that writers have to solve all the time.
I guess a typical solution is to have your text read by a few people, and hope they are a representative sample. Or just hope that you are lucky and got it right.
In theory, one of the goals of general education is to define what is supposed to be common knowledge, and to make it so. But clearly people forget many things they learned at school, and learn many things from media or internet.
Maybe there are some standardized exams where you could look at the results, if they are published in details, to see what students actually learned.
But I suspect that whatever method you use, at the end there will be a scale… some things generally known by 99% of your target population, some known by 90%, 80%, 50%, 20%, 10%, 1%, 0.1% etc.
I guess a typical solution is to have your text read by a few people, and hope they are a representative sample. Or just hope that you are lucky and got it right.