"substantial confusion" is correct and usable in written English.
You can use it when referring to confusion or misunderstanding that is intense and difficult to overcome. For example: "The two parties found themselves in a state of substantial confusion, as neither could agree on a resolution for their dispute."
This has generated substantial confusion and frustration among physicians and patients alike.
One journal editor, who wished to remain anonymous, said changing names causes "substantial confusion".
There is also substantial confusion over the legal rights of cohabiting couples as compared to married couples.
Although a footnote indicated that the donations in some cases came from employees of the named organizations, the lists have caused substantial confusion.
"There was always substantial confusion among roommates as to who called whom, and who had or had not paid the phone bill," Tom remembers.
As noted, there was substantial confusion for weeks after the Gulf spill about whether the company or different parts of government were making decisions.
The complexity of the institutional and legal landscape (multiple interacting agencies with multiple overlapping mandates and authority) creates substantial regulatory confusion.
Nine people referred to experiencing variations in intensity and duration of depression leading to substantial distress, confusion and feelings of hopelessness and a loss of control.
A substantial showing of confusion among either group might have convinced the trial court that continued use would lead to further confusion.
The last two responses represented almost a fifth of all responses, indicating a substantial degree of confusion and resignation among students when considering a future specialty [ 8].
The potential for confusion is substantial.
