3.1Data analysis & assisted Excel
The essentials in 30 seconds
- Three services: explain an inherited formula, generate the formula described in plain English, suggest analysis leads and their pitfalls.
- Generated formula = hypothesis: it only exists after testing on 2-3 cases with a known result; an AI analysis must be checked against sources.
- Structure without values: describing columns and types without the real figures gives expert help without exposure.
Running case — Amine and the inherited spreadsheet
Amine, a project manager in Algiers, inherits a tracking workbook full of nested formulas nobody understands. Instead of pasting the real figures, he describes the structure (column names, types) to the assistant: he gets the obscure formula explained step by step, gets the missing formula generated by naming the exact columns, then asks for 5 analysis leads and 3 interpretation mistakes. Each generated formula is tested on 2-3 rows with a known result before adoption.
This same case runs through the lesson, the diagram, the script and the 48h challenge.
1. Explain, generate, suggest leads
Faced with a spreadsheet, AI provides three services: explain an incomprehensible inherited formula (reverse-engineering taken-over files), generate the formula you describe in plain English by naming the exact columns, and suggest analysis leads (“which questions to ask of this data, which pitfalls?”).
With Copilot in Excel, everything happens inside the spreadsheet; with a general assistant, you paste an anonymised extract or, better, describe the structure without the values. Amine thus gets help without ever showing his real figures.
2. The safeguards: test and verify
A generated formula is tested on known cases: 2-3 rows whose result you know, before adoption. An AI analysis is checked against sources and professional judgement: AI analyses figures, you analyse a situation.
Correlation is not causation: conclusions remain yours, verified. And nothing identifying or confidential goes into an unapproved tool — describing the columns is most often enough (level 5 details the rule).
🔎 Concrete example — Getting help without showing the figures
Amine gets expert help without exposing the real values.
“My spreadsheet contains [column names]. Suggest 5 analyses and 3 pitfalls.”
→ expert help WITHOUT the real values.
Any generated formula: tested on 2-3 rows with a known result.Outcome: the structure (columns, types) is enough for relevant leads.
Lesson: testing on known cases separates a usable formula from a hypothesis.
Section vocabulary
- Formula explanation
- Step-by-step breakdown of a pasted formula: reverse-engineering inherited files.
Simple example: Amine pastes the obscure formula and asks what would break it.
What it is not: adopting a formula without understanding what it computes.
Reflex: ask for the explanation, then for the cases that would break it.
- Formula described in plain English
- Formula generated from a description naming the exact columns and the expected logic.
Simple example: “Display Follow-up if the date is over 30 days and the status is not Paid”.
What it is not: a vague request without column names.
Reflex: name the exact columns in every request.
- Analysis leads
- Analysis questions suggested from the columns, with the interpretation mistakes to avoid.
Simple example: Amine asks for 5 analyses and 3 pitfalls on his structure.
What it is not: a definitive conclusion adopted without verification.
Reflex: always ask for the pitfalls along with the leads.
- Description without data
- Giving the structure (column names, types) without the values: help without exposure.
Simple example: Amine describes his columns without pasting the Algiers figures.
What it is not: pasting the real identifying spreadsheet into an unapproved tool.
Reflex: describe first, paste only if harmless or tool approved.
- Test on known cases
- Validating a generated formula on 2-3 rows with a known result, before adoption.
Simple example: Amine tests the formula on two rows checked by hand.
What it is not: adopting the first suggestion straight away.
Reflex: test before copying anything into the real workbook.
In practice — The explanation / generation / leads trio
- Take the most obscure formula in one of your workbooks and ask: “Explain this formula step by step, then tell me what would break it”.
- Describe a formula you need, naming the exact columns — test the suggestion on 2 rows with a known result.
- Without showing your data: “My spreadsheet contains [your columns]. Suggest 5 relevant analyses and 3 interpretation mistakes to avoid”.
- If you have Copilot in Excel: redo the exercise inside it (see also the Copilot 365 guide, level 2) — compare the comfort.
Ready-to-say script — asking for help without exposing (30 s)
“My spreadsheet contains the columns [list] with [types]. Suggest 5 relevant analyses and 3 interpretation mistakes to avoid, without me pasting the values. Then I will ask you for a formula naming the exact columns, which I will test on known cases.”
To dictate or paste as is; never add the real figures in an unapproved tool.
Copy-paste template — safe data request
STRUCTURE (columns + types, WITHOUT values): _______________
NEED (explain / generate / leads): _______________
DESCRIBED FORMULA (exact columns + logic): _______________
TEST (2-3 rows with known result + verdict): _______________Small business / freelancer
Without Copilot: a general assistant + structure description covers 80% of common Excel needs.
SME in Algeria
Amine describes his project-tracking columns without exposing client figures, then tests each formula before sharing it with the team.
Office / employee
Internal spreadsheets: use the company-approved tool as soon as a real extract must be pasted.
Beginner
Start with a single inherited formula: get it explained, then get a simple variant generated and test it.
✓ Best practices
- “Explain this formula”: the ultimate weapon on inherited workbooks.
- Test every generated formula on cases with a known result.
- Describe the structure without the values to protect your data.
✗ Common pitfalls
- Adopting a generated formula without testing it.
- Pasting a real identifying spreadsheet into an unapproved tool.
- Confusing correlation and causation in conclusions.
Key takeaways
- “Explain this formula”: the ultimate weapon on inherited workbooks.
- A generated formula does not exist until it has passed the known-cases test.
- Describing the structure without the values: expert help without exposing data.
- Correlation is not causation: analysis conclusions remain yours, verified.
48h challenge — apply tomorrow
Get your most obscure formula explained, then test 1 generated formula on 2 known cases, without pasting any real data.
- I can get an inherited formula explained.
- I test every generated formula on known cases.
- I describe the structure without exposing the values.
Frequently asked questions
Can I paste a spreadsheet of figures into a public assistant?
Only if it contains nothing identifying or confidential (and in practice, that is rare). Anonymise or describe the structure — or use the company-approved tool. Level 5 details the rule.
Can AI do the full analysis for me?
It suggests leads and computations; business interpretation (why this peak? is this drop serious?) requires your knowledge of the context. AI analyses figures, you analyse a situation.
What must be done with a formula generated by AI?