The phrase "a commonly held assumption" is correct and usable in written English.
It can be used when discussing beliefs or ideas that are widely accepted by a group or society.
Example: "It is a commonly held assumption that exercise is beneficial for mental health."
Alternatives: "a widely accepted belief" or "a prevalent notion."
It is a commonly held assumption that Americans don't like to read authors who write in languages they don't understand.
The goal of ensuring adequate nutrition could easily be missed because of a commonly held assumption that hunger and nutrition are the same thing.
A commonly held assumption is that choosing to study part-time while continuing to teach is the best way to apply theory to practice, but the experience of some students suggests otherwise.
However, since the early 1920s the vast oil works have been dogged by erotic interpretations and, despite O'Keeffe's six decades of vigorous denial that her paintings were in any way sexual, it remains a commonly held assumption to this day.
A commonly held assumption within a sports league setting is that league affiliates interact with each other equally and that these engagements are largely facilitated by the league governing body or Federated Management Organisation (FMO).
This is a commonly held assumption and is related to the concept of "substantial equivalence", but it is factually wrong; the hypothesis in the quote is not discredited by the majority of scientists.
However, it does constitute a systematic attempt to explore the commonly held assumption that funding allocated to social science research is limited.
This challenges the commonly held assumption that streambed under a disconnected stream is always fully saturated, and limits the methods which introduce a negative or atmospheric pressure value at the IBSA to calculate seepage rate or assess stream-aquifer connectivity.
Together these studies question the commonly held assumption that this locus has a direct role in the evolution of brain size as a gross measure [ 16, 19, 56].
Despite the commonly held assumption that early August is an unsafe period to be admitted to hospital in England as residency starts the first Wednesday of August [1], previous work shows little evidence of an excess in deaths in the first week of August, when newly qualified junior doctors start work [2].
In the early 1900s, Karl von Frisch, an Austrian naturalist and winner of the Nobel Prize, questioned the commonly held assumption that fish were color-blind.
