Spreadsheet Assurance by "Control Around" is a Viable Alternative to the Traditional Approach

TL;DR

This paper explores a 'control around' method for spreadsheet assurance, which compares spreadsheet outputs with a shadow model to identify errors more efficiently than traditional formula-by-formula auditing.

Contribution

It introduces and discusses the viability of a 'control around' approach as an alternative to traditional spreadsheet auditing methods.

Findings

The 'control around' approach can reduce auditing time and cost.

It is effective when the shadow model accurately represents the spreadsheet logic.

The approach is preferable in scenarios with complex or large spreadsheets.

Abstract

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.