Issues

• [DOCS] Triangle.trend docstring says it counts days, but the code counts whole months

  casact/chainladder-python#1585 · Filter by author scks1 opened on Nov 11, 2026

• [BUG] TweedieGLM never passes alpha to TweedieRegressor

  casact/chainladder-python#1584 · Filter by author scks1 opened on Nov 11, 2026

• [FEAT] Gallery example recreating the SOA group health IBNR exercise (completion factors and PMPM projection)

  casact/chainladder-python#1583 · Filter by author scks1 opened on Nov 11, 2026

• [BRK] Add warning: Deprecate fillzero

  deprecation
  casact/chainladder-python#1582 · Filter by author github-actions opened on Nov 11, 2026

• [BRK] Deprecate fillzero

  deprecationparent issue

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  Bug

  casact/chainladder-python#1581 · Filter by author henrydingliu opened on Nov 11, 2026

• [BUG] DevelopmentCorrelation gives fully tied columns full weight, so triangles that never develop get T = 1

  casact/chainladder-python#1578 · Filter by author scks1 opened on Nov 10, 2026

• [BUG] DevelopmentCorrelation reports T = 1 with no data and takes I from the development columns

  casact/chainladder-python#1577 · Filter by author scks1 opened on Nov 10, 2026

• [BUG] shift on a pattern stores its display labels as development, and development then raises TypeError

  casact/chainladder-python#1576 · Filter by author scks1 opened on Nov 10, 2026
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• [BUG] Arithmetic with a pattern gives the result the pattern's valuation date

  casact/chainladder-python#1575 · Filter by author scks1 opened on Nov 10, 2026
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• [BUG] Sparse arithmetic with a one-origin Triangle fills only the first origin when development lengths differ

  casact/chainladder-python#1574 · Filter by author scks1 opened on Nov 10, 2026
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• [BUG] Triangle.cumsum raises TypeError: nancumsum() got an unexpected keyword argument 'keepdims'

  casact/chainladder-python#1573 · Filter by author scks1 opened on Nov 10, 2026
  2

• [BUG] MackChainladder gives a different Mack standard error for an incremental triangle

  casact/chainladder-python#1571 · Filter by author scks1 opened on Nov 10, 2026

• [FEAT] Check estimator parameter values before fit, including estimators loaded with read_json

  casact/chainladder-python#1569 · Filter by author scks1 opened on Nov 9, 2026
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• [FEAT] Record the seed each random draw used, and handle random_state=0 and RandomState instances as documented

  casact/chainladder-python#1568 · Filter by author scks1 opened on Nov 9, 2026
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• [FEAT] Opt-in check for duplicate keys in the Triangle constructor

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  casact/chainladder-python#1567 · Filter by author scks1 opened on Nov 9, 2026
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• [RUFF] Add ruff rule D401

  Great First Contribution! 🌱

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  Task

  casact/chainladder-python#1566 · Filter by author genedan opened on Nov 9, 2026

• [FEAT] cross-reference datasets with papers

  Triage Pending ⚠️
  casact/chainladder-python#1565 · Filter by author henrydingliu opened on Nov 9, 2026
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• [BUG] MackChainladder fails on a triangle fit with Development(groupby=...)

  casact/chainladder-python#1563 · Filter by author scks1 opened on Nov 9, 2026
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• [FEAT] One-year claims development result (Merz–Wüthrich) for MackChainladder

  casact/chainladder-python#1543 · Filter by author scks1 opened on Nov 7, 2026
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• [BRK] Change data type of triangle.development from Series to Index

  casact/chainladder-python#1538 · Filter by author genedan opened on Nov 4, 2026
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• [BRK] Change data type of triangle.index from DataFrame to Index/MultiIndex

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  casact/chainladder-python#1537 · Filter by author genedan opened on Nov 4, 2026 · v1.0.0
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• [BRK] Consider retaining the datatype of the new development axis after triangle.dev_to_val()

  casact/chainladder-python#1536 · Filter by author genedan opened on Nov 4, 2026
  2

• Triangle.sum() is typed as TriangleProtocol, hiding the Triangle API from type checkers

  Triage Pending ⚠️
  casact/chainladder-python#1527 · Filter by author yuuuxt opened on Nov 3, 2026

• Runtime-attached Triangle methods (mean, to_csv, groupby aggregations, etc.) are unknown to Pyright/Pylance and ty

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  casact/chainladder-python#1526 · Filter by author yuuuxt opened on Nov 3, 2026 · v0.11.0
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• [ENH] Support medial averages in CaseOutstanding

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  Feature

  casact/chainladder-python#1512 · Filter by author priyam0k opened on Oct 26, 2026
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