Six attempts
Each attempt changed one thing and was measured against the base model it started from.
1 · E4B, 17,885 conversations
It learned the style, not the facts
Fluent Catalan with an Andorran tone, and more confident errors. Benchmark 30.3 → 31.0 %, no real change. Open questions fell from 9.1 to 5.6 %.
Lesson: seeing a fact once in a sentence does not make it retrievable.
2 · E4B, 18,738 conversations
Cleaner data was not enough
284 answers that cited an invisible document were rewritten, and 943 basic questions were added. Benchmark 30.0 %. Open questions stayed at 5.8 %.
Lesson: 5 % more facts does not move the needle.
3 · E4B pilot, 50 facts
A small test that worked
Each fact was asked 11 different ways, with answers worded differently each time. Recall on 50 new questions rose from 6 to 66 %. A new error appeared: it mixed up similar facts.
Lesson: repetition with variation works, and similar facts need contrast examples.
4 · E4B, 28,679 conversations
The recipe at full size
830 verified facts, 124 contrast groups. Recall rose from 7 to 36 %. Benchmark 30.3 → 32.9 %, +2.6 points with a 95 % interval of −0.6 to +5.9, so not significant.
Lesson: the taught facts stick, and the open questions no longer get worse.
5 · 12B, 28,679 conversations
A bigger model that scored worse
Benchmark 35.0 % against 37.4 % for its base. It answered with a sentence instead of a letter in 67 of 604 multiple-choice questions, because the training data had no multiple-choice conversation at all.
Lesson: fine-tuning can erase a format the base model already knew.
6 · 12B, 30,288 conversations
Format fixed, figure inflated
1,609 multiple-choice practice questions were added. No answer without a letter now. Recall rose from 12 to 47 %. Benchmark 37.4 → 43.3 %, but most of that gain is not knowledge.
Lesson: the filter against similar questions was too loose.