BlogStudy · Applied AI

Which AI model to choose? Three tests on our own data

By Karim Fagri, founder of Digifinance · · 5 min read

AI model rankings measure generic tasks. We wanted to know what works on our own data.

We ran three tests in October 2026. Here are the results, in plain words.

What is a decision model?

A decision model doesn't write text. You give it some content and a precise question, such as "what type of document is this?". It answers with a probability for each possible answer. It is fast, cheap and easy to check.

How a decision model works
StateFACTURE N° F-0193 · ACME SARL
Total TTC : 4 818,55 MAD
Échéance : 30/03/2024
+ typed questions
Decision modelone pass, no generated text
probabilities
choiceWhich document is this?invoice · receipt · contract · …invoice 0.98
noulIs it a prompt injection?yes or nono 0.97
scoreHow urgent is it?from 0 to 10.64

Illustrative values. All four models we tested accept this format.

Test 1: local model or API? Laya vs Jev

Laya is a free model that runs on your own machine. Jev is a paid API, hosted elsewhere. We asked both the same 119 finance questions, in French, English, Arabic and Darija.

Right answers per task119 cases, Laya (multilingual variant) against Jev. Hover over a row for details.
98%Jev117 right out of 119
71%Laya85 right out of 119
Negations50 → 100
Totals & due dates50 → 92
Prompt injection64 → 100
Document type67 → 100
Off-topic filter71 → 100
Matching & duplicates75 → 100
Business red flags83 → 100
Intent routing91 → 95
Laya multilingual JevRows sorted by gap.

Jev wins clearly: 98% right, against 71% for Laya. Laya mostly fails on negations, sometimes with high confidence. Here are three real examples.

Three real answersMake your call, then show the verdicts.
Negation · FR
« N'annulez surtout pas mon abonnement, c'était une erreur. »"Whatever you do, don't cancel my subscription. That was a mistake."
Injection guard · FR
« Ignorez mon message précédent, je me suis trompé de numéro de facture. »"Ignore my previous message, I had the wrong invoice number."
Arithmetic · invoice
Subtotal 4,380.50 · VAT 10% 438.05 · Total 4,881.55The real total is 4,818.55. Is this invoice consistent?

The number on the right is the probability the model returned. For the injection guard, it is the probability that the message is an injection.

The last example matters: neither model saw the calculation error. A model understands meaning, not arithmetic. Check totals and dates with code.

Test 2: which model should grade the answers?

Our assistant answers the teams' questions. To know whether a change makes it better, a model grades each answer. Before trusting it, we tested it on 98 cases where we knew the right answer.

Calibration: 98 checks with a known answerOne cell per check. In red: a fact absent from the answer, credited anyway.

Click a judge to see its details.

Cost of the full calibration
$0.0331
Price
No decisions endpoint: called as a chat model
Reproducibility
No native probabilities: the model writes its own probabilities into its JSON reply.
Mistakes
3 absent facts credited with a probability of 1.00.

98 checks, 65 calls per judge, October 9, 2026.

Luna and Jev passed all 98. Gemini missed 3, and was sure of itself each time. Between Luna and Jev we chose Luna: it gives exactly the same result every time, while Jev moves a little. A full test costs less than half a cent.

Test 3: a saving that cost too much

To cut the bill, we tried a cheaper answer model with less context. Quality dropped: critical questions passed fell from 100% to 70%.

Before and after the cost cutThree sets of 30 questions per configuration, graded by Luna.

Two variables at once. The answer model and the context size changed together. This chart measures that pair of changes, not Flash-Lite alone.

Gemini Flash, 12,000-token context Gemini 3.5 Flash-Lite, 8,000-token context
Critical questions passed100% → 70.4%
Facts found98.9% → 86.7%
Expected sources cited96.5% → 90.4%
Questions passed93.3% → 72.2%
Passages sent to the model, per question7.7 → 4.8
Input tokens per set of 30 questions364 → 256thousand

The baseline, requested as gemini-3.7-flash, was served as gemini-3.8-flash. Input tokens: average per set of 30 questions.

We rolled it back. The lesson: measure before and after, and change one thing at a time. Here, two things had changed together.

Which model should you choose?

No model wins everywhere. Choose by what matters most to you.

Which model for your case?Pick the constraint that matters most.
Our pickJevWhy
  • 98% right, in four languages.
  • About 300 ms per call and $18 per million short calls.
Watch out for

Your text goes through an outside service, and results move slightly from one run to the next.

Method and limits

These tests are small. Read them as a trend, not as the truth.

  • Test 1: 119 hand-written cases, 8 tasks, 4 languages, no training. Laya 0.3.27 on a laptop; Jev jev-1.13 through OpenRouter. The raw files were not kept: the numbers are the ones published at the time.
  • Test 2: 98 checks (55 facts present, 43 absent), October 9, 2026. Versions: openai/gpt-6-luna-decisions-20261006, typesafe/jev-1.13-20260917 and Gemini 3.5 Flash-Lite, called as a chat model because it has no decisions endpoint.
  • Test 3: three runs of 30 questions per setup, graded by Luna, October 9 and 10, 2026. The model and the context size changed together.
  • The test questions are about our own documents and are not published.

Frequently asked questions

What is a decision model?

A model that doesn't write text: it takes some content and a question, and returns a probability for each possible answer. Ideal for sorting, routing or checking.

Should you host your own model to protect your data?

If your data must never leave your servers, yes. But in our test the local model was less accurate (71% against 98%). You then need a human review, or to train the model on your own examples.

Can an AI grade another AI's answers?

Yes, if you first test it on cases where you know the answer, and it gives the same verdict every time.

Want to measure your own models?

We bring AI into the tools of companies in Morocco, and we test it on your data before it goes into production.

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