Tools · Model Health Check
Would your modelsurvive a review?
Twenty yes/no questions drawn from the FAST standard and the ICAEW Financial Modelling Code. Five minutes, a score out of 100, a breakdown by category, and a report that tells you exactly what to fix first.
BE HONEST. THE SCORE IS ONLY USEFUL IF THE ANSWERS ARE.
Model health score
Answer the twenty questions
- STRUCTURE0/4
- INPUTS0/4
- CALCULATION0/4
- CHECKS0/4
- GOVERNANCE0/4
01 · STRUCTURE
How the model is laid out and how calculation flows through it.
01Inputs, calculations and outputs are kept on separate sheets or clearly separated areas.
Mixing them is the single most common source of hidden errors and hard-coded overrides. · FAST · ICAEW
02The timeline is consistent: the same periods sit in the same columns on every sheet.
A shifted column on one sheet silently breaks every cross-sheet link. · FAST
03Each row holds one calculation, copied unchanged across the full timeline.
One formula per row is what makes a model auditable in seconds rather than days. · FAST
04Calculation flows in one direction with no circular references (or one documented, switchable circularity).
Circularities hide errors, slow the model and make iteration settings a point of failure. · FAST · ICAEW
02 · INPUTS
Where assumptions live, how they are labelled and how cases are switched.
05There are no hard-coded numbers inside formulas; every assumption sits in a labelled input cell.
A number buried in a formula cannot be found, flexed or challenged. · FAST · ICAEW
06Inputs are visually distinct, with consistent colour coding for inputs, calculations and links.
Colour is how a reviewer knows what they are allowed to change. · FAST · ICAEW
07Every input has a unit and a source: where it came from and who owns it.
An assumption with no source cannot be defended in front of a board. · ICAEW
08A scenario switch flips the whole model between cases from a single cell.
Without it, scenarios become copies of the file and drift apart within a week. · FAST
03 · CALCULATION
Whether the arithmetic is readable, consistent and self-contained.
09Formulas are short enough to read in the formula bar; long logic is broken into steps on separate rows.
A formula nobody can read is a formula nobody can check. · FAST
10Balances follow a corkscrew: opening plus movements equals closing, built the same way for cash, debt and fixed assets.
Consistent corkscrews are why the balance sheet balances by construction, not by luck. · FAST
11Timing is handled with flags and masks (start, end, active-period switches) rather than IF logic embedded in every row.
Flags keep the arithmetic visible and let you audit timing in one place. · FAST
12The model has no links to other workbooks and needs no macros to calculate.
External links break when files move; macros hide logic from the reviewer. · ICAEW
04 · CHECKS
Whether the model can tell you when it is wrong.
13There is a dedicated checks sheet, and a single overall check flag is visible on every sheet.
If the model can go wrong silently, it will. · FAST · ICAEW
14The balance sheet balances and cash reconciles in every period, and a check would catch it if not.
The balance check is the model's heartbeat. · FAST · ICAEW
15Sensitivities and stress cases have been run, and the model responds sensibly to extreme inputs.
A model that only works on the base case is a calculator, not a model. · ICAEW
16Someone other than the builder has reviewed the model.
Builders cannot see their own blind spots. Every serious model has a second pair of eyes. · ICAEW
05 · GOVERNANCE
Whether someone else could pick it up, trust it and run it.
17Version control is in place: consistent file naming, a change log and one clearly current version.
"Which version is this?" is the most expensive question in a board meeting. · ICAEW
18Outputs are decision-ready: a summary dashboard shows what leadership needs without opening a calculation sheet.
If the answer lives on a calc sheet, the decision will be made on something else. · FAST
19There is a cover or guide sheet explaining purpose, structure, key assumptions and how to use the model.
Documentation is what turns a personal spreadsheet into a business asset. · ICAEW
20A competent person new to the model could understand and run it within an hour.
Transparency is the whole point of the standards. This is the test of all the others. · FAST · ICAEW
YOUR REPORT
Answer all twenty questions and your report appears here: the score, what to fix first, and what we would recommend.
Take it with you
The standards behind the score
Built to be questioned, not admired.
Every question maps to a principle in one of the two standards Naked Finance builds to. The score is not a judgement on the person who built the model; it is a measure of how much the business can trust the numbers it is making decisions on, and how quickly someone new could pick it up.
FAST
Flexible, Appropriate, Structured, Transparent. The standard for how a model is built: one calculation per row, inputs separated from calculations, timing by flags, consistent structure across sheets.
ICAEW Financial Modelling Code
The Institute's principles for models that decisions depend on: clear purpose and documentation, no hard-coded numbers, checks that catch errors, version control and independent review.
Nothing you answer is stored unless you ask us to email the report. · All tools · Training and resources