Why this repo exists
A sibling model, theshivam7/whisper-medium-indian-english,
was fine-tuned and evaluated on TIE_shorts' official splits, which have speaker overlap between
train and test. That model showed no net WER improvement over the pretrained baseline. This
repo re-runs the same fine-tune with speaker overlap eliminated, to check whether the earlier
result was simply masked by a favorable split.
It wasn't, and the honest result is worse than a null. This checkpoint (training seed 42)
raises WER from 14.42% (pretrained, same decoding pipeline) to 16.17%, a +1.75pp
regression that survives Holm-Bonferroni correction for multiple comparisons (p = 0.048, paired
speaker-cluster bootstrap, 985 clips / 280 speakers).
Training-set size vs. speaker-disjointness. TIE_shorts' official test speakers are so
entangled with train that removing them keeps only 567 of 7,200 train clips (3.8 of 46.9 hours;
51 of 331 speakers), so this run differs from the official-split fine-tune in both speaker
overlap and training-set size (~13× smaller). A size-matched speaker-overlapping control (same
567-clip budget, 3 seeds, speaker overlap preserved) isolates the two effects: all 3 control seeds
land flat at 14.33–14.40%, indistinguishable from the 14.42% pretrained baseline, no significant
effect in any seed. Since the control trains on the same ~567-clip budget as the disjoint runs
below (the shared no-embedded-audio filter can drop a clip or two per seed; e.g. this seed-42 run
trains on 566), a one-clip difference cannot explain the disjoint runs' regression. Speaker-disjointness
is the cause: removing speaker overlap exposes that part of the official split's fine-tuning
signal was speaker memorization, not genuine acoustic/language adaptation. Full breakdown in the
GitHub repo's finetune_comparison.md.
⚠️ This checkpoint is not representative of "the" fine-tuning effect
This project trained the same recipe with 3 seeds to check whether a null/negative result
from one run was just seed variance. It wasn't uniform:
Table with columns: Seed, WER (transcript_clean), Δ vs pretrained, Holm-adjusted p| Seed | WER (transcript_clean) | Δ vs pretrained | Holm-adjusted p |
|---|
| 42 (this checkpoint) | 16.17% | +1.75 pp | 0.048 (significant) |
| 43 | 14.80% | +0.38 pp | 0.116 (not significant) |
| 44 | 15.20% | +0.79 pp | 0.163 (not significant) |
Only this seed (42) reaches significance; seeds 43/44 fall within the study's minimum detectable
effect (≈1.2pp) and are indistinguishable from no effect. The seed-to-seed spread (1.37pp) is
itself larger than the effect being measured. The defensible claim from the full study is:
fine-tuning on the speaker-disjoint training subset (567 clips) shows no evidence of improving
WER, and at least one seed (this one) shows evidence of making it measurably worse. Per the
size-matched control above, that regression traces to speaker-disjointness itself, not to the
13×-smaller training set. Do not treat this checkpoint's 16.17% as "the" expected WER of
speaker-disjoint fine-tuning: treat it as one of three seed outcomes, published for exact
reproducibility of that specific result.
Full methodology, all 3 seeds' raw transcripts, the size-matched control, and the statistical
analysis: indian-asr-bench.
Intended use
This is a research artifact documenting an evaluation-validity and fine-tuning-stability finding,
not a recommended checkpoint for transcription. If you need Indian-English Whisper inference,
plain openai/whisper-medium performs at least as
well per this study, with no fine-tuning risk.
Training and evaluation data
- Train:
train split of raianand/TIE_shorts, with every speaker present in test removed:
567 clips / 3.8 hours / 51 speakers after the standard ≤30s/non-empty filters (the official
split keeps 7,200 clips / 46.9 hours / 331 speakers; this seed's run trains on 566 after the
no-embedded-audio filter).
- Test:
test split of raianand/TIE_shorts (986 clips): identical set used for every other
model in the benchmark, so results are directly comparable.
- Targets: the dataset's gold
Transcript field (English, transcribe task).
License
Apache 2.0, matching the base model. The TIE_shorts dataset carries its own license.