On 223 of 250 PES examination questions with Polish chain-of-thought, the mean normalised pivot of Bielik-PL-11B-v3.0-Instruct minus that of Bielik-11B-v3.0-Instruct is -1.0875 (95% interval -1.1008 to -1.0741; bootstrap p-value with 2,000 resamples, Holm-adjusted over the three benchmarks, 0).

Relation: Paired difference

metric

Normalised pivotQuantity compared.

subject

Bielik-PL-11B-v3.0-InstructModel after the tokenizer change.

comparator

Bielik-11B-v3.0-InstructModel before the tokenizer change.

benchmark

PES examination questionsBenchmark the questions come from.

value

-1.0875 normalised shareMean over questions of subject minus comparator.

interval low

-1.1008 normalised shareLower bound of the 95% paired bootstrap interval.

interval high

-1.0741 normalised shareUpper bound of the 95% paired bootstrap interval.

p holm

0 p-valueTwo-sided bootstrap p-value, Holm-adjusted over the three benchmarks.

scope

223 of 250 PES examination questions usable in both models, answers with Polish chain-of-thoughtQuestions and answers compared.

Method and evaluation protocol

Teacher-forced forward pass of each answer through the MLX bf16 model with a custom loop over the 50 blocks; after each block the residual stream at generated positions is decoded through the final RMSNorm and output head with an fp32 softmax; masses on English- and Polish-labelled pieces are pooled over reasoning positions whose next token is language-labelled. Answers below 0.95 teacher-forcing agreement, with a failed round-trip or without language positions are excluded. Paired difference of normalised pivot restricted to one benchmark.

Dataset

Greedy answers of both models to 800 Polish STEM questions (250 GSM8K-PL, 300 LLMzSzŁ STEM, 250 PES) with Polish chain-of-thought, and their graded outcomes; questions usable in both models after the lens exclusions.Version: unspecified · Access: restricted

Reported results

-1.0875 [-1.1008, -1.0741], Holm p 0 over three benchmarks.

Uncertainty and replication

95% paired item bootstrap interval within the benchmark (2000 resamples, seed 20260704); Holm adjustment over the three benchmarks. A p-value of 0 means that no bootstrap resample reached zero; with 2000 resamples the smallest non-zero value is 0.001.

Evidence references

analysis.json · publichttps://github.com/stw2/tokenizer-science-tax/blob/a9246a60690bf1627e4cc56095f64e3307508bb2/experiments/E08-latent-pivot/results/analysis.jsonmetrics.json · publichttps://github.com/stw2/tokenizer-science-tax/blob/a9246a60690bf1627e4cc56095f64e3307508bb2/experiments/E08-latent-pivot/results/metrics.json

Limitations

Logit lens, not a tuned lens: early-layer decodings are noisy. The vocabulary partitions label 16163 Polish and 1289 English pieces for APT4 and 1665 and 6116 for the Mistral-derived tokenizer, and were built from re-serialised MLX tokenizer files without an equivalence check. The design was written after the lens run started. The Polish-model lens file combines records from two invocations separated by an unrecorded rewrite of the lens script.