However, the creator(s) may not only be expressing their own perspective or bias: their words may reflect those of a larger section of society at that time. If a creator represents the views of a larger group, we can say that the individual 'represents' the opinions of that group of people. In this way, you can talk about a creator’s ‘representativeness’.
As the leader of his country, the president of the United States of America may represent the views of Americans.
The easiest way to assess a source’s representativeness is to consider what other group of people would have shared (or agreed with) the views expressed in the source at the time of its creation. A creator can either represent the views of a majority of people (mainstream) or of a small group (marginalised) at a particular point in time. Often, you need to draw upon your own historical knowledge of the period to decide this.
A source may be representative of a social group's:
Demonstrating source representativeness in your writing:
Most ancient accounts of Roman history were written by the wealthy elites, so their works reflect the views of this social class (as found in Stevenson, 2015, 56).
Thousands of papyrus fragments from Oxyrhynchus preserve the personal thoughts of children as they learnt to write and, as such, provides rare insights into this segment of ancient Egyptian society (as found in Bean, 1979, 21).
Cicero was a senator and an optimate and so his opinions reflect this view. However, his opinion that “ …” (as found in Jones, 1985, 49) was probably shared by most in the Senatorial order at that time and provides unique insight into this dominant position.