Source-reviewed knowledge center

Practical guidance with explicit provenance and source links.

Each guide shows who prepared it, its current review status, sources, publication date, last-reviewed date, and correction history. Expert review is not claimed until a named reviewer has approved the text.

Model assumptions

A Model Output Is Not Valid Until Its Assumptions Are Checked

Coefficients, p-values, and confidence intervals are conditional on design and model assumptions that must be examined, documented, and stress-tested.

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Independent review

Why Data Quality Should Be Reviewed by Someone Else

Independent review can detect systematic errors, undocumented assumptions, and confirmation bias that the person who cleaned the data may no longer see.

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Data cleaning

The Data-Cleaning Log Is Part of the Scientific Record

Every correction, transformation, recode, merge, and exclusion that can affect a result should be traceable to a rule, reason, reviewer, and data version.

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Protocol integrity

When the Protocol, Registry, and Manuscript Tell Different Stories

A three-document crosswalk reveals unexplained changes in outcomes, sample size, eligibility, analyses, and study status before publication.

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Outcome definition

An Outcome Must Be Defined Before It Is Measured

A reproducible endpoint specifies the variable, participant-level metric, method of aggregation, time point, assessor, and decision rules.

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Research feasibility

Sample Size Is Also a Feasibility Decision

A scientifically justified target still fails if the institution cannot recruit, retain, measure, and analyze that sample responsibly.

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Sample size

Power and Precision Answer Different Sample-Size Questions

A sample-size calculation should declare whether the study is designed to test a target difference or estimate a quantity within an acceptable margin.

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Decision communication

How Research Leaders Should Communicate Uncertainty

Decision-ready communication shows what is known, what remains plausible, which assumptions matter, and what action is justified now.

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Uncertainty

What a Confidence Interval Tells You That a P-Value Cannot

An interval helps readers judge the estimated effect, its precision, and which clinically important possibilities remain compatible with the data.

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Change control

When Should an Analysis Change Require Formal Approval?

A proportionate amendment pathway distinguishes routine implementation details from changes that alter the scientific question, bias risk, or interpretation.

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Analysis planning

Prespecified and Exploratory Analyses Can Coexist

A credible report separates tests planned before outcome data were examined from analyses prompted by patterns found later.

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Missing-data governance

A Missing-Data Policy Is a Governance Decision

Institutions should define when missingness requires documentation, prevention, sensitivity analysis, escalation, or a limit on the conclusion.

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Missing data

Missing Is Not a Single Category in Medical Data

Blank, unknown, not applicable, not collected, and structurally unavailable values represent different events—and collapsing them can undermine analysis.

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Data governance

Who Owns the Meaning of a Research Variable?

Data definitions need named decision rights, because an unowned variable can change meaning across forms, systems, analysts, and reports.

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Data provenance

The Minimum Data Dictionary Every Medical Study Needs

A compact, versioned variable specification prevents hidden disagreements about definitions, codes, units, timing, and missingness from reaching the analysis.

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Before calculating sample size, define the estimand

A sample-size formula cannot rescue an ambiguous population, outcome, contrast, time point, or handling of intercurrent events.

  • Write the population, treatment or exposure conditions, outcome, time point, and population-level contrast before choosing inputs.
  • Distinguish a detectable effect from the smallest clinically meaningful effect.
  • Record the source and uncertainty for every event rate, variance, correlation, loss-to-follow-up, and design-effect assumption.
  • Plan sensitivity scenarios rather than presenting one number as certain.
Correction history

Version 1.0 · 24 July 2026 · Initial publication. No corrections recorded.

Five statistical claims a p-value cannot support

Statistical significance alone does not establish clinical importance, causality, absence of bias, model validity, or replicability.

  • A small p-value does not measure the size or importance of an effect.
  • A non-significant result is not proof that two conditions are equivalent.
  • Association does not become causal because confounders were entered into a model.
  • Model output is not reliable until assumptions, missingness, multiplicity, and data quality are addressed.
Correction history

Version 1.0 · 24 July 2026 · Initial publication. No corrections recorded.

What a resident should be able to teach back before defense

A defensible project requires the researcher to explain why the design and analysis answer the question—and where they do not.

  • State the research gap, primary objective, and primary outcome in plain language.
  • Explain the sampling pathway and the most important selection-bias risk.
  • Interpret effect estimates and confidence intervals before discussing p-values.
  • Name limitations, their likely direction, and the claims that should therefore be avoided.
Correction history

Version 1.0 · 24 July 2026 · Initial publication. No corrections recorded.

De-identification is a risk review, not a single delete command

Removing names is necessary but may not be sufficient when dates, rare conditions, geography, free text, or linked variables can identify a person.

  • Start with authority, purpose, recipients, environment, and minimum necessary fields.
  • Separate direct identifiers and linkage keys from the analytical working copy.
  • Review combinations of indirect identifiers and small cells.
  • Record residual risk, access rules, retention, and the person who approved release.
Correction history

Version 1.0 · 24 July 2026 · Initial publication. No corrections recorded.

Responsible AI disclosure needs purpose, location, and verification

Naming a tool is not enough. Authors should document what it did, where its output appears, and how humans verified accuracy and originality.

  • Do not list an AI system as an author.
  • Do not upload confidential manuscripts or identifiable data where confidentiality is not assured.
  • Verify factual claims, calculations, citations, images, and wording against authoritative sources.
  • Follow the target journal and institution even when their required disclosure is stricter.
Correction history

Version 1.0 · 24 July 2026 · Initial publication. No corrections recorded.

Corrections

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