Inheriting a Spreadsheet: the Audit Checklist

Someone hands you a workbook and asks for the number by noon. Do not trust it yet. A handed-down spreadsheet hides stale calculations, typed-over formulas, and references that quietly drifted. Run this checklist before you rely on a single cell.

Built-in AI tutor. Open it with the Ask AI button at the bottom-right, or with the “Check my list with the AI tutor” button in section 2. In Chrome 148 or later it usually runs on your device. Otherwise, your question and what you type on this page go to the class AI through the course server. Work the diagnostic yourself first, then ask it to check your reasoning. It coaches. It will not just hand you the answer.

Seven passes before you trust it

Run these top to bottom the first time you open an inherited workbook.

The number does not match. Why?

You believe a cell should compute =A1+B1. The result is wrong, or it will not update when you change A1. Before you assume the data is bad, work down the likely causes. Most are about the workbook, not the math.

Your turn

A colleague says “this cell is just A1 plus B1, but the total is wrong.” In the box, list every cause you can think of and how you would check each one. Then ask the tutor to review your list; it will tell you what you missed.

Expected: =A1+B1  |  A1 = 100, B1 = 50  |  Cell shows: 0 (and does not change when A1 changes)

Tables vs ranges: make the references legible

Half of what makes an inherited workbook hard to read is that its formulas point at bare cell rectangles. Excel Tables fix that, and prevent a whole class of the bugs the checklist hunts for.

A plain rangeA named rangeAn Excel Table (Ctrl+T)
How a formula reads=SUM(C2:C5000)=SUM(Revenue)=SUM(sales[revenue])
Grows with dataNo, you re-point it by handOnly if you redefine itYes, automatically
Formula fills downManual, can driftManualAuto, every row identical
Filter buttonsYes, Data → Filter (one per sheet)Yes, Data → Filter (one per sheet)Yes, on by default, one per Table
Total rowNoNoYes, one checkbox

Name a range

Select the cells, type a name in the Name Box (top-left, beside the formula bar), press Enter. Now =SUM(Revenue) works anywhere. Manage them under Formulas → Name Manager, which is also where you find the stale or broken names a previous author left behind.

Why Tables are the durable choice

  • Readable references: sales[revenue] says what it is; C2:C5000 does not.
  • Self-maintaining: the Table auto-expands as rows are added, so a SUM never silently misses the new rows. Missed rows are a common inherited-workbook error.
  • Consistent column logic: one formula applies to the whole column, which kills the fill-down drift the checklist looks for.
  • Lighter to reason about: you bound the data once; you are not re-selecting giant rectangles or padding ranges “just in case,” which also keeps the file leaner.

When you inherit a workbook of bare ranges, converting the core data to a Table is often the single highest-value cleanup you can make.