Spreadsheet Assurance by "Control Around" is a Viable Alternative to the   Traditional Approach
  The traditional approach to spreadsheet auditing generally consists of auditing every distinct formula within a spreadsheet. Although tools are developed to support auditors during this process, the approach is still very time consuming and therefore relatively expensive. As an alternative to the traditional "control through" approach, this paper discusses a "control around" approach. Within the proposed approach not all distinct formulas are audited separately, but the relationship between input data and output data of a spreadsheet is audited through comparison with a shadow model developed in a modelling language. Differences between the two models then imply possible errors in the spreadsheet. This paper describes relevant issues regarding the "control around" approach and the circumstances in which this approach is preferred above a traditional spreadsheet audit approach. 
Harmen Ettema, Paul Janssen, Jacques de Swart