Auditing & Assurance Services 6th Edition by Timothy Louwers

Exercise 5

Negative Assurance in Review Reports. One portion of the report on a review services engagement is the following: "Based on my review, I am not aware of any material modifications that should be made to the accompanying financial statements in order for them to be in conformity with generally accepted accounting principles [or another framework for financial reporting]."
Required:
a. Is this paragraph a "negative assurance" given by the accountants?
b. Why is negative assurance generally prohibited in audit reports?
c. What justification is there for permitting negative assurance in a review services report on unaudited financial statements and on interim financial information?