Cite the release, not the latest link
A persistent dataset address can resolve successfully while no longer providing the evidence used in a published calculation. This methods note compares FORCE11 citation principles, DataCite versioning guidance, and Research Data Alliance recommendations for evolving data. A fictional index revision separates corrected observations from expanded coverage and demonstrates why collection identifiers, release identifiers, subsets, and analysis outputs answer different questions. The discussion examines immutable releases, timestamped queries, stable sorting, checksums, and persistent landing pages without presenting any one repository design as mandatory. It distinguishes exact reproduction from scientific robustness and explains why reproducibility does not override legitimate restrictions. The resulting recommendation is a compact citation backed by recoverable authorised evidence and an inspectable method, with explicit limits when retrieval becomes impossible.
A reproducible chart starts before the chart
A chart's source link does not preserve the decisions that produced its values. This essay explains how a reproducible public graphic begins with a defined question, comparable quantities, and an explicit analysis record. NOAA's Arctic temperature chapter illustrates the importance of geographical coverage, water-year timing, baselines, and distinct input products. A simplified baseline example separates a changed reference from a changed observation, while noting that other processing choices can also differ. The proposed compact recipe retains input versions, retrieval dates, selections, weighting, filters, completeness rules, and transformation order. Climate and Forecast history conventions support this record but do not replace explanation. Accessible tables, labelled uncertainty, and distinctions between measurements and estimates help readers recover the calculation even when they disagree with its interpretation.