# Health Economics Metrics

> A comprehensive introduction to health economics math, examples, and reasoning, written for software engineers building for national health service organizations worldwide. Each file covers one metric or concept: definition, why it matters, the math, a worked example, the software engineering connection, pitfalls, and sources.

Each topic is one page: definition, why it matters, the math, a worked example, the software engineering connection, pitfalls, and sources. Pages are in the canonical locale (en-gb-oxendict); the same topics are published in 55 other locales, linked below. Every locale's topic URL has the same path shape: https://health-economics-metrics.github.io/<locale>/topics/<slug>/.

## Economic reasoning foundations

- [Opportunity cost](https://health-economics-metrics.github.io/en-gb-oxendict/topics/opportunity-cost/): the value of the best alternative forgone; why fixed budgets make every choice a displacement
- [Discounting and time preference](https://health-economics-metrics.github.io/en-gb-oxendict/topics/discounting-and-time-preference/): present values, the 3.5% Green Book/NICE rate
- [Analysis perspective](https://health-economics-metrics.github.io/en-gb-oxendict/topics/analysis-perspective/): payer vs provider vs societal: whose costs count
- [Time horizon](https://health-economics-metrics.github.io/en-gb-oxendict/topics/time-horizon/): how long to count costs and effects, and horizon gaming
- [Marginal vs average cost](https://health-economics-metrics.github.io/en-gb-oxendict/topics/marginal-vs-average-cost/): why freeing a bed doesn't save its average cost
- [Cash-releasing vs non-cash-releasing savings](https://health-economics-metrics.github.io/en-gb-oxendict/topics/cash-releasing-vs-non-cash-releasing/): the honesty test for every "time saved" claim
- [Sensitivity analysis](https://health-economics-metrics.github.io/en-gb-oxendict/topics/sensitivity-analysis/): tornado diagrams; which assumption carries your case
- [Probabilistic sensitivity analysis](https://health-economics-metrics.github.io/en-gb-oxendict/topics/probabilistic-sensitivity-analysis/): Monte Carlo, CEACs, probability of being right
- [Expected value of perfect information](https://health-economics-metrics.github.io/en-gb-oxendict/topics/expected-value-of-perfect-information/): pricing the pilot before you run it
- [Expected value of sample information](https://health-economics-metrics.github.io/en-gb-oxendict/topics/expected-value-of-sample-information/): pricing a *specific* proposed study, not eliminating all uncertainty
- [Real options valuation](https://health-economics-metrics.github.io/en-gb-oxendict/topics/real-options-valuation/): pricing the option to expand a phased project later, rather than the option to gather information first
- [Human capital approach vs friction cost method](https://health-economics-metrics.github.io/en-gb-oxendict/topics/human-capital-and-friction-cost/): two ways to value lost productivity, a 2x+ difference in reported cost
- [Dominance and the efficiency frontier](https://health-economics-metrics.github.io/en-gb-oxendict/topics/dominance-and-efficiency-frontier/): eliminating options nobody should pick

## Outcome measures

- [Quality-adjusted life year (QALY)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/quality-adjusted-life-year/): the common currency of health value
- [Disability-adjusted life year (DALY)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/disability-adjusted-life-year/): the burden-side mirror; global health's metric
- [EQ-5D](https://health-economics-metrics.github.io/en-gb-oxendict/topics/eq-5d/): the instrument behind most QALY utility weights
- [Time Trade-Off (TTO) Utility Elicitation](https://health-economics-metrics.github.io/en-gb-oxendict/topics/time-trade-off-utility/): how a utility weight is actually elicited from a respondent
- [Incremental cost-effectiveness ratio (ICER)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/incremental-cost-effectiveness-ratio/): extra cost per extra unit of health
- [Willingness-to-pay thresholds](https://health-economics-metrics.github.io/en-gb-oxendict/topics/willingness-to-pay-thresholds/): NICE £20–30k/QALY and the world's other lines
- [Value of a statistical life (VSL)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/value-of-a-statistical-life/): the labour-market alternative to threshold-based valuation
- [Net monetary benefit (NMB)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/net-monetary-benefit/): value minus cost, done properly
- [Life-years gained](https://health-economics-metrics.github.io/en-gb-oxendict/topics/life-years-gained/): survival math, and the evLYG equity variant
- [Health-adjusted life expectancy (HALE)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/health-adjusted-life-expectancy/): population-level healthy-years accounting
- [QALY shortfall and severity modifiers](https://health-economics-metrics.github.io/en-gb-oxendict/topics/qaly-shortfall-and-severity-modifiers/): why sicker populations' QALYs count more
- [Work productivity and activity impairment (WPAI)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/work-productivity-and-activity-impairment/): absenteeism vs presenteeism, the hidden half of the cost

## Economic analysis types

- [Cost-effectiveness analysis (CEA)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/cost-effectiveness-analysis/): cost per natural unit of outcome
- [Cost-utility analysis (CUA)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/cost-utility-analysis/): cost per QALY; comparing unlike interventions
- [Cost-benefit analysis (CBA)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/cost-benefit-analysis/): everything in money; Green Book NPV
- [Cost-minimization analysis (CMA)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/cost-minimization-analysis/): cheapest option, after proving equivalence
- [Cost-consequence analysis (CCA)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/cost-consequence-analysis/): the disaggregated table; NICE's preference for digital health
- [Budget impact analysis (BIA)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/budget-impact-analysis/): affordability, as distinct from value
- [Return on investment (ROI)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/return-on-investment/): the shared metric, with declared parameters
- [Social return on investment (SROI)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/social-return-on-investment/): monetizing what markets don't price
- [Cross-currency ICER comparison](https://health-economics-metrics.github.io/en-gb-oxendict/topics/cross-currency-icer-comparison/): PPP vs market FX; the conversion choice that can flip an adoption decision

## Health system operational economics

- [Bed days saved](https://health-economics-metrics.github.io/en-gb-oxendict/topics/bed-days-saved/): the workhorse benefit, and its valuation traps
- [Length of stay](https://health-economics-metrics.github.io/en-gb-oxendict/topics/length-of-stay/): the hospital's cycle time
- [Readmission rate](https://health-economics-metrics.github.io/en-gb-oxendict/topics/readmission-rate/): the health system's change failure rate
- [Did-not-attend (DNA) rate](https://health-economics-metrics.github.io/en-gb-oxendict/topics/did-not-attend-rate/): missed appointments; the purest waste metric
- [Emergency attendance avoidance](https://health-economics-metrics.github.io/en-gb-oxendict/topics/emergency-attendance-avoidance/): upstream intervention economics
- [National tariff and unit costs](https://health-economics-metrics.github.io/en-gb-oxendict/topics/national-tariff-and-unit-costs/): the NHS price book and costing infrastructure
- [Referral to treatment (RTT)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/referral-to-treatment/): the 18-week standard as a lead-time metric
- [Waiting list impact](https://health-economics-metrics.github.io/en-gb-oxendict/topics/waiting-list-impact/): converting saved hours into patients seen
- [Practitioner time](https://health-economics-metrics.github.io/en-gb-oxendict/topics/practitioner-time/): valuing bottleneck capacity, not wages
- [Workforce retention](https://health-economics-metrics.github.io/en-gb-oxendict/topics/workforce-retention/): turnover costs and burnout economics
- [Avoidable outsourcing costs](https://health-economics-metrics.github.io/en-gb-oxendict/topics/avoidable-outsourcing-costs/): repatriating premium-rate work
- [Downstream resource optimization](https://health-economics-metrics.github.io/en-gb-oxendict/topics/downstream-resource-optimization/): unblocking the role everyone waits on
- [Earlier intervention](https://health-economics-metrics.github.io/en-gb-oxendict/topics/earlier-intervention/): the economics of treating before progression
- [Value-generating capacity (operational turnaround)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/value-generating-capacity-operational-turnaround/): minting capacity without hiring
- [Hard cash-releasing savings (deficit defense)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/hard-cash-releasing-savings-deficit-defence/): deleting budget lines; the CFO's metric

## HTA frameworks and prevention economics

- [Health technology assessment (HTA)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/health-technology-assessment/): NICE, ICER (US), CADTH: who decides what's worth buying
- [Markov cohort simulation](https://health-economics-metrics.github.io/en-gb-oxendict/topics/markov-cohort-simulation/): how a multi-cycle HTA model is actually simulated cohort-by-cycle
- [NICE Evidence Standards Framework](https://health-economics-metrics.github.io/en-gb-oxendict/topics/nice-evidence-standards-framework/): risk-tiered evidence requirements for digital health
- [Germany's DiGA fast-track](https://health-economics-metrics.github.io/en-gb-oxendict/topics/diga-fast-track/): apps on prescription; provisional listing with an evidence deadline
- [Number needed to treat (NNT)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/number-needed-to-treat/): effort-per-benefit units that keep claims honest
- [Population attributable fraction (PAF)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/population-attributable-fraction/): how much disease burden a risk factor is really worth chasing
- [Prevention economics](https://health-economics-metrics.github.io/en-gb-oxendict/topics/prevention-economics/): why prevention is cost-effective but rarely cost-saving
- [Screening economics](https://health-economics-metrics.github.io/en-gb-oxendict/topics/screening-economics/): Wilson–Jungner, PPV collapse at low prevalence, alert fatigue
- [Number needed to screen (NNS)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/number-needed-to-screen/): NNT's screening-programme-level analogue
- [Avoided downstream costs](https://health-economics-metrics.github.io/en-gb-oxendict/topics/avoided-downstream-costs/): cost offsets and the rules that make them credible
- [Multi-criteria decision analysis (MCDA)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/multi-criteria-decision-analysis/): weighted scoring when a single threshold isn't enough
- [Carbon footprint per QALY](https://health-economics-metrics.github.io/en-gb-oxendict/topics/carbon-footprint-per-qaly/): the NHS net-zero commitment meets cost-per-QALY

## Software engineering and digital delivery

- [Cost of delay](https://health-economics-metrics.github.io/en-gb-oxendict/topics/cost-of-delay/): £/week or QALYs/week of non-delivery; the master bridge metric
- [DORA metrics](https://health-economics-metrics.github.io/en-gb-oxendict/topics/dora-metrics/): delivery performance, translated into health-economics terms
- [Flow metrics](https://health-economics-metrics.github.io/en-gb-oxendict/topics/flow-metrics/): Little's Law, WIP, flow efficiency; the shared queueing math of hospitals and pipelines
- [WSJF and CD3](https://health-economics-metrics.github.io/en-gb-oxendict/topics/wsjf-and-cd3/): value-density prioritization; the backlog as a QALY league table
- [SPACE and DevEx](https://health-economics-metrics.github.io/en-gb-oxendict/topics/space-and-devex/): multi-dimensional productivity; the EQ-5D lesson for engineering metrics
- [Technical debt](https://health-economics-metrics.github.io/en-gb-oxendict/topics/technical-debt/): principal, interest, and chronic-disease economics for codebases
- [Total cost of ownership (TCO)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/total-cost-of-ownership/): maintenance is 50–80%; the naive-drug-price error in software
- [Cloud unit economics (FinOps)](https://health-economics-metrics.github.io/en-gb-oxendict/topics/cloud-unit-economics/): cost per unit of output; the digital service's reference cost
- [Exact-cents cost allocation](https://health-economics-metrics.github.io/en-gb-oxendict/topics/exact-cents-cost-allocation/): the largest-remainder method; splitting a total so the parts sum exactly back
- [Currency-safe cost rollup](https://health-economics-metrics.github.io/en-gb-oxendict/topics/currency-safe-cost-rollup/): exact-decimal `Money`, not `f64`, for totals that must reconcile to the penny
- [Build vs buy](https://health-economics-metrics.github.io/en-gb-oxendict/topics/build-vs-buy/): risk-adjusted comparison with the delay term priced
- [Benefits realization](https://health-economics-metrics.github.io/en-gb-oxendict/topics/benefits-realization/): auditing that forecast benefits actually happened
- [GDS service metrics](https://health-economics-metrics.github.io/en-gb-oxendict/topics/gds-service-metrics/): cost per transaction, satisfaction, completion, take-up

## AI acceleration

- [AI developer productivity](https://health-economics-metrics.github.io/en-gb-oxendict/topics/ai-developer-productivity/): Copilot RCT vs METR RCT; efficacy vs effectiveness
- [AI return on investment](https://health-economics-metrics.github.io/en-gb-oxendict/topics/ai-return-on-investment/): the 95%-no-return finding and what the 5% did differently
- [Inference unit economics](https://health-economics-metrics.github.io/en-gb-oxendict/topics/inference-unit-economics/): cost per token, and modeling relentless price decline
- [AI quality metrics](https://health-economics-metrics.github.io/en-gb-oxendict/topics/ai-quality-metrics/): hallucination rates as harm rates with a price
- [Clinical AI evaluation](https://health-economics-metrics.github.io/en-gb-oxendict/topics/clinical-ai-evaluation/): sensitivity, specificity, AUROC, and why prevalence rules the economics
- [AI regulatory evaluation](https://health-economics-metrics.github.io/en-gb-oxendict/topics/ai-regulatory-evaluation/): FDA SaMD, PCCPs, and the economics of model updates

## Consumer health apps and devices

- [Engagement metrics](https://health-economics-metrics.github.io/en-gb-oxendict/topics/engagement-metrics/): engagement as clinical dose
- [Retention and churn](https://health-economics-metrics.github.io/en-gb-oxendict/topics/retention-and-churn/): the law of attrition; retention curves as treatment windows
- [Activation and uptake](https://health-economics-metrics.github.io/en-gb-oxendict/topics/activation-and-uptake/): the front gates of the value funnel
- [Adherence and persistence](https://health-economics-metrics.github.io/en-gb-oxendict/topics/adherence-and-persistence/): MPR, PDC, effective engagement, minimum effective dose
- [Patient-reported outcomes](https://health-economics-metrics.github.io/en-gb-oxendict/topics/patient-reported-outcomes/): PROMs, PREMs, and the MCID honesty bar
- [Digital endpoints and biomarkers](https://health-economics-metrics.github.io/en-gb-oxendict/topics/digital-endpoints-and-biomarkers/): from sensor telemetry to regulator-grade evidence
- [Wearable validation](https://health-economics-metrics.github.io/en-gb-oxendict/topics/wearable-validation/): MAPE, agreement statistics, wear-time, completeness
- [Remote patient monitoring economics](https://health-economics-metrics.github.io/en-gb-oxendict/topics/remote-patient-monitoring-economics/): CPT code stacks and hospital-at-home substitution
- [Health app unit economics](https://health-economics-metrics.github.io/en-gb-oxendict/topics/health-app-unit-economics/): CAC, LTV, PMPM, and ROI vs VOI
- [Reach and equity](https://health-economics-metrics.github.io/en-gb-oxendict/topics/reach-and-equity/): RE-AIM; population impact = reach × effectiveness
- [Concentration index](https://health-economics-metrics.github.io/en-gb-oxendict/topics/concentration-index/): a formal statistical measure of socioeconomic-related health inequality

## Locales

- [العربية (ar-001)](https://health-economics-metrics.github.io/ar-001/)
- [العربية - مصر (ar-eg)](https://health-economics-metrics.github.io/ar-eg/)
- [বাংলা (bn-001)](https://health-economics-metrics.github.io/bn-001/)
- [বাংলা - বাংলাদেশ (bn-bd)](https://health-economics-metrics.github.io/bn-bd/)
- [Cymraeg (cy-001)](https://health-economics-metrics.github.io/cy-001/)
- [Cymraeg - Y Deyrnas Unedig (cy-gb)](https://health-economics-metrics.github.io/cy-gb/)
- [Dansk (da-001)](https://health-economics-metrics.github.io/da-001/)
- [Dansk - Danmark (da-dk)](https://health-economics-metrics.github.io/da-dk/)
- [Deutsch (de-001)](https://health-economics-metrics.github.io/de-001/)
- [Deutsch - Deutschland (de-de)](https://health-economics-metrics.github.io/de-de/)
- [English (en-001)](https://health-economics-metrics.github.io/en-001/)
- [English - Europe (en-150)](https://health-economics-metrics.github.io/en-150/)
- [English - Great Britain (en-gb)](https://health-economics-metrics.github.io/en-gb/)
- [English - Great Britain - Oxford (en-gb-oxendict)](https://health-economics-metrics.github.io/en-gb-oxendict/)
- [English - United States (en-us)](https://health-economics-metrics.github.io/en-us/)
- [Español (es-001)](https://health-economics-metrics.github.io/es-001/)
- [Español - España (es-es)](https://health-economics-metrics.github.io/es-es/)
- [Eesti (et-001)](https://health-economics-metrics.github.io/et-001/)
- [Suomi (fi-001)](https://health-economics-metrics.github.io/fi-001/)
- [Suomi - Suomi (fi-fi)](https://health-economics-metrics.github.io/fi-fi/)
- [Français (fr-001)](https://health-economics-metrics.github.io/fr-001/)
- [Français - France (fr-fr)](https://health-economics-metrics.github.io/fr-fr/)
- [हिन्दी (hi-001)](https://health-economics-metrics.github.io/hi-001/)
- [हिन्दी - भारत (hi-in)](https://health-economics-metrics.github.io/hi-in/)
- [Bahasa Indonesia (id-001)](https://health-economics-metrics.github.io/id-001/)
- [Bahasa Indonesia - Indonesia (id-id)](https://health-economics-metrics.github.io/id-id/)
- [Íslenska (is-001)](https://health-economics-metrics.github.io/is-001/)
- [Italiano (it-001)](https://health-economics-metrics.github.io/it-001/)
- [Italiano - Italia (it-it)](https://health-economics-metrics.github.io/it-it/)
- [日本語 (ja-001)](https://health-economics-metrics.github.io/ja-001/)
- [日本語 - 日本 (ja-jp)](https://health-economics-metrics.github.io/ja-jp/)
- [한국어 (ko-001)](https://health-economics-metrics.github.io/ko-001/)
- [한국어 - 대한민국 (ko-kr)](https://health-economics-metrics.github.io/ko-kr/)
- [Nederlands (nl-001)](https://health-economics-metrics.github.io/nl-001/)
- [Nederlands - Nederland (nl-nl)](https://health-economics-metrics.github.io/nl-nl/)
- [Norsk (no-001)](https://health-economics-metrics.github.io/no-001/)
- [Norsk - Norge (no-no)](https://health-economics-metrics.github.io/no-no/)
- [Polski (pl-001)](https://health-economics-metrics.github.io/pl-001/)
- [Polski - Polska (pl-pl)](https://health-economics-metrics.github.io/pl-pl/)
- [Português (pt-001)](https://health-economics-metrics.github.io/pt-001/)
- [Português - Portugal (pt-pt)](https://health-economics-metrics.github.io/pt-pt/)
- [Русский (ru-001)](https://health-economics-metrics.github.io/ru-001/)
- [Русский - Россия (ru-ru)](https://health-economics-metrics.github.io/ru-ru/)
- [Svenska (sv-001)](https://health-economics-metrics.github.io/sv-001/)
- [Svenska - Sverige (sv-se)](https://health-economics-metrics.github.io/sv-se/)
- [Kiswahili (sw-001)](https://health-economics-metrics.github.io/sw-001/)
- [ไทย (th-001)](https://health-economics-metrics.github.io/th-001/)
- [Türkçe (tr-001)](https://health-economics-metrics.github.io/tr-001/)
- [Українська (uk-001)](https://health-economics-metrics.github.io/uk-001/)
- [Українська - Україна (uk-ua)](https://health-economics-metrics.github.io/uk-ua/)
- [اردو (ur-001)](https://health-economics-metrics.github.io/ur-001/)
- [اردو - پاکستان (ur-pk)](https://health-economics-metrics.github.io/ur-pk/)
- [Tiếng Việt (vi-001)](https://health-economics-metrics.github.io/vi-001/)
- [中文 (zh-001)](https://health-economics-metrics.github.io/zh-001/)
- [中文 - 中国大陆 (zh-cn)](https://health-economics-metrics.github.io/zh-cn/)
- [中文 - 台灣 (zh-tw)](https://health-economics-metrics.github.io/zh-tw/)

## Optional

- [Site map of topics as JSON](https://health-economics-metrics.github.io/llms.json): machine-readable index with source Markdown URLs
- [Sitemap](https://health-economics-metrics.github.io/sitemap.xml): every published page
- [Search index](https://health-economics-metrics.github.io/search-index.json): full text of every page
- [Source repository](https://github.com/health-economics-metrics/health-economics-metrics.github.io): Markdown source, one directory per topic