Work in progress
The handbook is being written. The chapters below are the planned contents, and the download opens as soon as the finished file is ready.
Defensive Spreadsheeting Handbook
A practical introduction to spreadsheet risks, from LineUpYourDucks, creators of HSAA.
DUCKS
Defensive Spreadsheeting
Handbook
Inside the handbook
Introduction
Overview
Why defensive spreadsheeting matters and how the risks fit together.
Chapter 1
Hardcoded values inside formulas
Numbers buried in formulas that quietly go out of date.
Chapter 2
Broken cell references (#REF!)
How deleted rows and columns break calculations.
Chapter 3
Circular references
When a formula depends on its own result.
Chapter 4
Inconsistent formulas across ranges
One different formula hiding in a column of identical ones.
Chapter 5
Input controls and data validation
Stopping bad entries before they spread.
Chapter 6
Fragile lookup ranges
Lookups that miss new rows or point to the wrong place.
Chapter 7
Formatting used as data
Colours and styles that carry meaning formulas cannot see.
Chapter 8
Structural and merge issues
Merged cells and layouts that break sorting and analysis.
Chapter 9
File bloat and hidden data
Unused ranges, hidden sheets and leftover content.
Chapter 10
Volatile functions and calculation loops
Formulas that recalculate constantly and slow workbooks.
Free handbook
An introduction to each risk with concrete examples.
HSAA engine
Audits your workbooks locally to help you find these risks.
Member course
The full original module PDFs with progress checklists.
A growing course
The course starts with eleven modules. Clients are invited to suggest new chapters based on the spreadsheet problems they encounter.