Assurance services can come in variety of forms and are meant to provide the firm contracting the CPA with pertinant information in order to ease decision making. For example, the client could request that the CPA carefully go over all of the numbers and math that are on the client's mortgage website to ensure that all of the calculations and equations are correct.
Read more: http://www.investopedia.com/terms/a/assurance-services.asp#ixzz3XizZEHXX
Follow us: @Investopedia on Twitter