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Insights / AI and automation

Claude vs ChatGPT: test your existing work first

Benchmark scores do not predict your results. Run the work you already trust through both models, then let the owner decide on the evidence.

Exhibit 1Should the business switch models on this evidence?

11 of 12 cases pass and one citation fails, so the owner holds the switch and keeps the existing route.

Illustrative figures, not client data.

In short

  • Test the work you already run: the same approved cases and files, on both models.
  • Set the pass marks before you see an answer, and open every citation behind a decision.
  • Hold the switch while a defect is open, keep the old route as the fallback and name who can reverse the change.

A new model scores well on a public benchmark. Your invoices, sales policies and dispatch notes are not in it.

The owner’s decision is narrower: does the work you already trust still pass if the model changes? Test that on your own approved cases, then decide.

Freeze the existing work
Exhibit 2

Twelve approved cases run twice on each route give 24 outputs to compare

ItemAgreed value
DatasetApproved pack, version 1
FunctionsFinance, sales and operations
Cases4 per function, 12 in all
Runs2 per case, on each route
RecordModel, plan, date and tools enabled

Sample. The approved cases and their answers are fictional.

Illustrative figures, not client data.

Start with work you already trust. Keep the approved inputs, expected answers and reviewer notes together. Give both routes the same files and instructions. OpenAI’s evals guide says a test data set should represent ‘the type of data you expect your prompt to work with’. Choose cases that cost something when they are wrong, such as a quote, a supplier reply or a dispatch exception.

OpenAI says models ‘sometimes produce different output from the same input’. Run each case twice, and keep the awkward answers too.

Set the pass marks first
Exhibit 3

Four pass marks are written down before either model answers

CheckRequired outcomeEvidence kept
CalculationsMatch the approved workingWorking shown
CitationsSupport every claim relied onSource opened, words matched
AccessNo record the user may not seeTwo denied requests
Missing evidenceThe answer flags the gapA source left out on purpose

Illustrative figures, not client data.

Write the gates before you read either answer. A fluent reply cannot choose its own marking scheme. Anthropic’s documentation says: ‘Most use cases need multidimensional evaluation along several success criteria.’

Include a missing source and an access-denied case. Open every citation behind a decision and compare its words with the claim. Anthropic says citations help you ‘track and verify the sources behind each response’. Mark each gate pass or fail with a reason, so two reviewers reach the same answer. Record the vendor checks in the AI vendor evidence annex.

Keep every correction visible
Exhibit 4

One sales policy is misstated, so the candidate passes 11 of 12 cases

FunctionCasesExisting acceptedCandidate acceptedReview minutes
Finance44430 / 20
Sales44335 / 30
Operations44425 / 20
Total12121190 / 70

Sample figures, not a model test. Review minutes are existing route / candidate. A case passes only if both runs pass.

Illustrative figures, not client data.

The candidate misstates one sales policy, though it cites the right document. The reviewer marks the case failed and keeps the corrected wording beside the original output.

Log every intervention, including prompt changes and manual sums. If you repair the instructions, rerun both routes.

Checking the candidate took 20 minutes less. That is trial effort in hours, not a cash saving. Software and running costs sit outside this test.

Check access and plan the reversal
Exhibit 5

Two access probes pass, yet one citation failure still holds the switch

ControlFilled decision
Test dataApproved fictional records only
Access probes2 denied requests, both denied
Open defect1 citation failure
Owner decisionHold the switch
Reversal ownerOperations lead
FallbackExisting route and settings kept

Illustrative figures, not client data.

Passing the access probes does not repair the citation failure. Keep the existing prompts, settings and files until the owner accepts revised evidence.

Keep personal information out of the trial unless its use has been assessed. The OAIC says ‘Take steps to minimise the amount of personal information that is input into the AI system.’ Get privacy advice for your circumstances.

OpenAI advises running evals ‘on every change’. Re-run the pack when the model, the plan or the workflow changes. Anthropic advises ‘thorough testing of your applications with the new models well before the retirement date’.

What to do first
Exhibit 6

Twelve cases and four pass marks turn a model change into a decision

  1. 01Pick 12 approved cases

    Four each from finance, sales and operations, with the answers already agreed.

  2. 02Write the pass marks

    Calculations, citations, access and missing evidence, before any answer is read.

  3. 03Run both routes twice

    Same files, same instructions. Keep every output and every correction.

  4. 04Decide on a dated record

    Name the owner, the open defect, the fallback and who can reverse the change.

One page and twelve cases are enough to start. Run the pack before you renew or change a plan.

Common questions

Which is better, Claude or ChatGPT?

Neither wins for every business. Test your own approved cases against agreed answers, because public scores measure other work.

Can a benchmark settle the switch?

No. OpenAI separates industry benchmarks for comparing models in isolation from specific tests of your own application. Your decision rests on the second kind.

Should both routes stay available?

Keep the approved fallback until the pass marks are met. Then re-run the pack whenever the model, the plan or the workflow changes.

Can customer data go into the test?

Use approved fictional records first. Personal information needs an assessment and privacy advice, and the OAIC advises minimising it.

Renzo Demartini, Chartered Accountant and finance executive, Canberra

Renzo Demartini

Chartered Accountant (CA ANZ) and finance executive, based in Canberra. Practical AI and automation for SMEs, and adviser to owners, CEOs and boards on integration and finance.

Changing the AI your business relies on? I lead the change across the workflows it touches, starting with a Diagnostic that ends in clear priorities.

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