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Kaggle Competitions 2026: CASMI and Playground S6E10

Two live Kaggle competitions worked end to end: Enveda CASMI 2026, a featured competition that ranks candidate molecular structures for MS/MS spectra, and Playground S6E10, a tabular ROC-AUC competition on airline satisfaction. In both, decisions were made on cross-validation and the public leaderboard was treated as a noisy sample.

Role fit

Data ScientistMachine LearningRanking and Retrieval

Quick technical review

The case study in four points.

Full methodology

Problem

For each MS/MS spectrum of an unknown natural product, rank candidate structures so that the right one appears as high as possible in the top 25. The candidates are not given: they have to be retrieved from structure libraries first.

Architecture

An own pipeline first: spectral retrieval, analog propagation from library neighbours, a bond-cleavage fragment explanation, biotransformations of spectral analogs as extra candidates, and a LightGBM LambdaRank ranker validated on 600 frozen queries…

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An own pipeline first: spectral retrieval, analog propagation from library neighbours, a bond-cleavage fragment explanation, biotransformations of spectral analogs as extra candidates, and a LightGBM LambdaRank ranker validated on 600 frozen queries from libraries it never trained on. It reached a public score of 0.309. The community then built a public pipeline around spectrum simulation (ICEBERG and GLACIER) and a PubChem popularity prior that scores 0.420; the current entry fuses that pipeline with this ranker as an extra rank list and scores 0.422, 8 Oct 2026 snapshot rank 353 of 2,797.

Results

CASMI 2026: public 0.422, 8 Oct 2026 snapshot rank 353 of 2,797

Limitations & scope

Public-leaderboard ranks move daily and are not final. The CASMI score of 0.422 rests on a public community pipeline; the own pipeline alone scores 0.309. The S6E10 stack includes predictions published by other Kagglers, credited in the repository;…

Read complete note

Public-leaderboard ranks move daily and are not final. The CASMI score of 0.422 rests on a public community pipeline; the own pipeline alone scores 0.309. The S6E10 stack includes predictions published by other Kagglers, credited in the repository; the foundation-model members were not trained here.

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Kaggle 2026 Research Challenges conceptual editorial research illustration

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Original portfolio illustration. Diagrams are conceptual; verified methods and results appear in the linked case study. This is not an application screenshot.

CASMI 2026: public 0.422, 8 Oct 2026 snapshot rank 353 of 2,797

Own CASMI pipeline alone: 0.309

S6E10: public 0.96177, 8 Oct 2026 snapshot rank 34 of 1,126

S6E10 nested stack CV 0.96211

Project proof

Verified external evidence

Last verified 2026-10-08

Problem and approach

CASMI 2026: problem

For each MS/MS spectrum of an unknown natural product, rank candidate structures so that the right one appears as high as possible in the top 25. The candidates are not given: they have to be retrieved from structure libraries first.

CASMI 2026: what was built

An own pipeline first: spectral retrieval, analog propagation from library neighbours, a bond-cleavage fragment explanation, biotransformations of spectral analogs as extra candidates, and a LightGBM LambdaRank ranker validated on 600 frozen queries from libraries it never trained on. It reached a public score of 0.309. The community then built a public pipeline around spectrum simulation (ICEBERG and GLACIER) and a PubChem popularity prior that scores 0.420; the current entry fuses that pipeline with this ranker as an extra rank list and scores 0.422, 8 Oct 2026 snapshot rank 353 of 2,797.

S6E10: what was built

29 own models (LightGBM, XGBoost, CatBoost and RealMLP) on features that treat Flight Distance as a route ID, use the original dataset as a teacher model rather than as extra rows, predict every rating from the other columns, and cross each rating with the passenger context; 10-fold versions of the strongest. They are stacked by logistic regression on logits with credited public predictions of tabular foundation models and other public OOF libraries. Nested stack CV 0.96211; public score 0.96177, 8 Oct 2026 snapshot rank 34 of 1,126.

Validation

Every stack score is nested: the combiner never scores rows it was fitted on. A held-out experiment showed why blends of reseeded models win on OOF and lose on the leaderboard (fold-averaged test predictions already contain that gain), and it is published as a notebook. The two final S6E10 submissions were chosen on CV only, one of them without any public OOF library, as a hedge against leaky public predictions.

What is not claimed

Public-leaderboard ranks move daily and are not final. The CASMI score of 0.422 rests on a public community pipeline; the own pipeline alone scores 0.309. The S6E10 stack includes predictions published by other Kagglers, credited in the repository; the foundation-model members were not trained here.

Architecture and analysis

  • Treats the public leaderboard as a noisy sample and selects on nested cross-validation.
  • Separates its own models from community pipelines and public predictions, and says which is which.
  • Publishes the analysis behind each decision as Kaggle notebooks.

Testing and validation

  • CASMI: retrieval, analog propagation, fragment explanation and a LambdaRank ranker, fused with the public spectrum-simulation pipeline
  • S6E10: feature screen, Kaggle-GPU stack members, nested-CV stacker and the blend-gap experiment

Operational value

  • CASMI 2026: public score 0.422, 8 Oct 2026 snapshot rank 353 of 2,797; the own pipeline alone reached 0.309.
  • S6E10: public score 0.96177, 8 Oct 2026 snapshot rank 34 of 1,126, from a nested stack CV of 0.96211.
  • Showed on held-out data that a seed blend gains about +0.00023 on OOF but about +0.00005 on fold-averaged test predictions.

How to inspect

  • Read the blend-gap notebook before the scores: it explains how the S6E10 submissions were chosen.
  • Read the CASMI pool notebook: a larger candidate pool made the score worse, and it says why.

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