Principles of Auditing & Other Assurance Services

Hello,

I am having trouble with this case,

Assume that you have been hiredby Willington, CPA, as a new staffassistant. He informs you that hisapproach to audits has always beento assess control risk at theonsiders necessary. However, hehas recently read an article inTheJournal of Accountancythatindicates that a more efficient auditmay sometimes be achieved byperforming some tests of controlsand thereby assessing control riskat a lower level. Willington showsyou the following table that camefrom the article: