"starting assumption" is correct and usable in written English.
It is used to refer to an initially accepted supposition or belief. For example, "My starting assumption is that the meeting will begin on time."
The starting assumption is: listen to what is being said.
Or at least that's the theory, and one that is a starting assumption for a great deal of policy making.
The starting assumption of both campaigns is that whoever wins two of the top three -- Florida, Pennsylvania and Ohio -- will win the presidency.
Jon Glasby, professor of health and social care and head of the School of Social Policy at Birmingham University, challenges the starting assumption.
My starting assumption is that, given the impact of online use, licensing is a more appropriate and flexible tool than exceptions.
Arabs are boycotting the discussions because they reject the starting assumption of Israel as a Jewish state, but are not numerous enough to challenge it.
Of course not: the independence decision is freighted with imponderables, starting assumptions and blind faith.
Once again, the experiment uncovered starting assumptions that people may have — perhaps without knowing it.
Lastly, we want to state common starting assumptions and see how recurring ideas would be written in this probability notation.
Unfortunately, these uncertainties are normally large enough to make the result of the calculation very dependent on starting assumptions about the value of input data.
More specifically, he treats wages and wage policy in such a way as to unmask the quite different starting assumptions of employer and employee.
