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Method page · Probability and statistics

Statistics for health evidence

Probability and statistics turn incomplete, delayed and biased health data into estimates with stated uncertainty. In this field they handle survey sampling, small numbers, under-reporting and shifting baselines, so that every indicator carries a range and the assumptions behind it rather than a single, overconfident number.

01In brief

The short answer.

Health statistics is the application of probability and statistics to incomplete, delayed and biased health data so that estimates carry stated uncertainty. It handles survey sampling, small numbers, under-reporting and shifting baselines, such as the expected deaths against which excess mortality is measured.

02Console

Tail fit, in outline.

The working screen behind this method: its structure, terms and states. Names are placeholders and values illustrative.

Tail fit

Health · Statistics for health evidence · Run R-6555

Shape parameter uncertainGCRI · Health Nexus

Return level curve

Method card

Method
Probability and statistics
Approach
peaks over threshold
Threshold
97th percentile
Label
MODELLED

Parameters

generalised Pareto fit

Shape ξ0.28−0.040.48heavy tail if above zero
Scale σ2.31.07.5units of the variable
Exceedances136declustered
Tail fit: the screen's structure, terms and states for Health.Placeholder names and illustrative values; a design, not a record or a live system.
03Application

What probability and statistics does here.

Probability and statistics provide the mathematical framework for describing uncertainty and learning from data. They underpin estimation, testing and prediction in every risk discipline. In health and biosecurity, statistical methods quantify the likelihood and uncertainty of losses across interconnected systems. They make the evidence behind risk decisions explicit and reproducible. The canonical description is on the STEM Commons.

Survey-weighted and small-area estimation

Household survey data are analysed with their sampling design, and small-area models borrow strength across districts to estimate subnational coverage, with credible intervals mapped beside the estimates.

Expected baselines for excess mortality

Models fitted to past mortality with trend and seasonality give the expected count against which observed deaths are compared, and the baseline's uncertainty is carried into the excess.

Correcting for under-ascertainment

Capture-recapture, serosurveys and multiplier methods estimate how many infections surveillance misses, so case counts are read against what they are likely to represent.

04Key terms

Terms used on this page.

Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.

TermDefinition
Excess mortalityDeaths above the number expected from a baseline, estimated with a model whose assumptions are stated.
Under-ascertainmentThe gap between true infections or cases and those detected by surveillance.
Survey weightA factor applied to each survey response so the sample represents the population.
05Geography

Access to care in Indonesia.

How far each division sits from a large city, with the roads and airports that carry patients and supplies, shown for Indonesia as an example geography for this subject.

How far each division sits from a large city, with the roads and airports that carry patients and supplies.Indicator derived from Natural Earth at map scale; a screening view, not an assessment.
GCRI · Health Nexus · fieldDESIGN FIGURE
06Canvas

The method as a run graph.

Data from the source register feeds the methods; calibration and an independent test gate the estimate and its limits; the decision stays with the competent authority.

Method canvas · Probability and statistics as applied hereDesign, not a record
Probability and statistics in Health Nexus: catastrophe model pipelineA stochastic event catalogue drives the hazard module; exposure and vulnerability turn intensity into damage; the financial module applies policy terms; event and year loss tables give exceedance curves, PML and TVaR. Design of the process, not a record of a run.

Fig. 01Nodes carry their type, metrics and state; connectors show what feeds what; the gates are the validation steps; the timeline is one application. Design of the method's use, not a record of a run.

07Data

What the method consumes.

Datasets and records used by probability and statistics on this platform, with the role each plays and the label its values carry. Sources are listed in the source register.

DataRoleLabel
DHS and MICS microdataDesign-based and model-based estimationESTIMATED
Vital registration seriesBaseline modellingOFFICIAL
SerosurveysCalibration of ascertainmentOBSERVED
Routine reporting with completeness metadataAdjustment for missing reportsREPORTED
08Validation

How results are checked.

Results are checked through diagnostics, cross-validation and sensitivity to assumptions. Independent replication confirms findings.

CheckHow it is done
Design-based varianceStandard errors account for clustering, stratification and survey weights
Posterior predictive checksModels must reproduce the observed data before they are used to estimate or predict
Sensitivity to priors and baselinesResults are recomputed under alternative assumptions and the spread is reported

Inference depends on assumptions about independence, distribution and sampling that may not hold. Small or biased samples limit reliability.

10Stewardship

Who maintains the method.

Systems Science and Modelling stewards probability and statistics for the Consortium and reviews how it is applied across platforms.

12Questions

Questions and answers.

What are the limits of probability and statistics in this field?
Inference depends on assumptions about independence, distribution and sampling that may not hold. Small or biased samples limit reliability.
How are results checked?
Results are checked through diagnostics, cross-validation and sensitivity to assumptions. Independent replication confirms findings.
Are the values on this page real?
The data names, roles and checks are real descriptions of practice. The canvas shows a design of the method's use, not a run; no result is reported here.
Where else is this method applied?
The canonical method page lists every platform that applies it.
Health Nexus

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