Dictionary

L

Label ExtensionTermIndication Extension, Approved-Use Extension, Label Expansion

An expansion of a drug's officially approved use to cover an additional population, indication, or dosing regimen not in its original approval.

Laboratory DataTermLab Data, Lab Test Results

Information derived from clinical laboratory testing, such as blood chemistry or biomarker assays, used to assess physiological status or treatment response.

Laboratory Information SystemTermLIS, Lab Information System

A specialist software system managing laboratory testing workflows, from sample tracking through result reporting, integrated with health records.

Laboratory OutcomeTermLab Outcome, Lab-Based Outcome

A clinical outcome derived from laboratory testing of blood, urine, or other biological samples, assessing physiological status or treatment response.

Labour EfficiencyTermLabor Efficiency, Staff Efficiency

A measure of how effectively an organisation uses staff time and effort to generate patient care activity, avoiding wasteful workforce use.

LambdaTermCost-Effectiveness Threshold Symbol, WTP Ceiling Symbol

The symbol conventionally used for the cost-effectiveness threshold, or willingness to pay per unit of health effect, in net monetary benefit analysis.

Landmark AnalysisConceptLandmark Method, Landmark Survival Analysis

A survival technique restricting analysis to patients event-free up to a predefined time point, then examining survival from that point forward.

Language BarrierTermLinguistic Barrier, Communication Barrier

An obstacle to healthcare arising from a mismatch between a patient's primary language and that used by providers or health materials.

Large Group MarketTermLarge Employer Market, Large Group Insurance

The insurance market segment serving employers above a defined size threshold, often with greater flexibility in plan design and pricing.

Last Observation Carried ForwardConceptLOCF, Carry-Forward Imputation

Last observation carried forward (LOCF) fills missing trial follow-up values with each participant's last observed value, assuming no change after dropout.

Last-Line TreatmentTermLast-Line Therapy, End-of-Line Treatment

The final treatment option considered after all other appropriate therapies have been exhausted or have failed to control disease.

Late AdopterTermLaggard, Late Majority

An individual or organisation beginning to use a new innovation relatively late in its diffusion, often facing greater scepticism or barriers.

Late EffectsTermLong-Term Sequelae, Delayed Treatment Effects

Health problems arising months or years after cancer treatment ends, resulting from the lasting impact of the disease or its treatment.

Latent Class AnalysisConceptLCA, Mixture Modelling

A technique identifying unobserved, categorical subgroups within a population from patterns of responses, assuming these fully explain the observed associations.

Latent Class ModelConceptLCM

A statistical model that assumes a population consists of unobserved subgroups with distinct preferences, estimating both each subgroup's traits and individual membership probability.

Latent Growth ModelConceptLatent Growth Curve Model, Growth Trajectory Model

A modelling framework representing an individual's trajectory using unobserved latent variables for starting level and rate of change, both varying across people.

Latent PeriodTermLatency Period, Pre-Infectious Period

The interval between exposure to an infectious agent and the point an infected person becomes capable of transmitting it to others.

Latent Transition AnalysisConcept

A technique modelling how individuals move between unobserved categorical subgroups over time, combining latent class analysis with a longitudinal framework.

Latent VariableConceptLatent Construct, Unobserved Variable

A latent variable is an unobserved quantity, such as health-related quality of life or preference class membership, estimated from observed indicators.

Latin Hypercube SamplingConcept

A sampling technique dividing each input's range into equally probable intervals and sampling each exactly once, giving more even coverage than simple random sampling.

Launch PriceTerm

The initial price at which a manufacturer introduces a new drug to a specific market, shaping both initial access and later reference pricing.

Launch PricingTerm

The overall strategy and process by which a manufacturer determines a new treatment's initial market price across its target markets.

Launch SequencingTerm

The strategic planning of the order a manufacturer introduces a treatment across national markets, influenced by international reference pricing linkages.

Launch StrategyTermProduct Launch Strategy, Go-to-Market Strategy, Launch Plan

The comprehensive plan a manufacturer develops for introducing a new treatment to market, covering pricing, market access, and evidence generation activities.

Launch TimingTerm

The strategic decision on when to introduce a new treatment to a specific market, influenced by regulatory, competitive, and reference pricing considerations.

Law of Large NumbersConceptLLN, Law of Averages

A theorem stating that as sample size increases, the sample average of a variable converges toward the true underlying population average.

Lead IdentificationTerm

An early drug discovery stage in which promising compounds from initial screening are characterised and prioritised for further development based on potency and selectivity.

Lead OptimisationTermLead Optimization

A drug discovery stage in which chemists modify a promising compound's structure to improve potency, selectivity, and pharmacokinetics before preclinical testing.

Lead Time BiasTerm

A bias in screening evaluations where earlier diagnosis appears to extend survival but only lengthens awareness of diagnosis, without delaying underlying disease progression.

League TableTerm

A table from a network meta-analysis displaying every treatment's estimated relative effect against every other treatment, organised for pairwise lookup.

League Table ConstructionTermICER Ranking, League Table Assembly

The process of assembling and ranking incremental cost-effectiveness ratios from multiple separate studies into a single comparative table to guide resource allocation.

Leakage RateTermBenefit Leakage, Targeting Leakage

The proportion of a targeted programme's total benefits that reach individuals outside its intended eligible population.

Lean HealthcareTerm

The application of lean management principles, from manufacturing, to healthcare process improvement, systematically identifying and eliminating waste in care delivery.

Lean MethodologyTermLean, Lean Management

A management approach, from manufacturing, focused on maximising value for the end customer while systematically minimising waste within a process.

Least Squares ApproximationConceptLeast Squares, Ordinary Least Squares

Least squares approximation estimates the coefficients of a chosen model by minimizing the sum of squared residuals between observed or target values and the corresponding model values.

Leave-One-OutConcept

A cross-validation form repeatedly refitting a model using all but one observation, using that observation to test accuracy, until each has served once.

Left CensoringConcept

A form of censoring in which an event is known to have occurred before an observed time, but its exact prior timing is unknown.

Left TruncationConceptDelayed Entry, Late Entry

Left truncation (delayed entry) occurs when people join a survival analysis risk set after time zero and are observed only if still event free at entry.

Legal EvidenceTermLegal Documentation, Legal-Implications Evidence

Documentation addressing the legal implications of an assessment decision, such as compliance with anti-discrimination or procedural fairness law.

Legal FeasibilityTermLegal Viability, Legal-Framework Feasibility

An assessment of whether a proposed policy is consistent with existing legal frameworks, or would require new legislative authority to implement.

Legal HTA AdvisorTermHTA Legal Advisor, Legal Counsel to HTA

An individual with specialised legal expertise guiding an assessment organisation on legal implications of its decisions and processes.

Legal ReviewTermLegal Examination, Legal Compliance Review

An examination of a proposed assessment decision or process to assess compliance with applicable legal requirements.

Legal StandardsTermLegal Requirements, Statutory Standards

The specific laws and regulations applicable to a healthcare organisation's operations, covering fraud prohibitions, privacy protections, and licensing requirements.

Leishmaniasis EconomicsTerm

The application of health economic evaluation to leishmaniasis, a sandfly-transmitted parasitic disease endemic to parts of the tropics and subtropics.

Length BiasTerm

A bias in screening evaluations arising because screening preferentially detects slower-growing cases that stay detectable longer, while aggressive cases are more often missed.

Length of StayTermLOS, Hospital Stay Duration

The total duration of a single patient's hospital admission, from the date of admission to the date of discharge.

Length Of Stay ManagementTermLOS Management, Stay Reduction

Strategies used to appropriately manage and, where clinically suitable, reduce hospitalisation duration, through care coordination and discharge planning.

Length of Stay ReviewTermLOS Review, Stay Duration Audit

An evaluation of a hospitalisation's duration relative to what would typically be expected, identifying efficiency opportunities or investigating prolonged stays.

LevelTerm

A specific value an attribute can take within a discrete choice experiment, such as a waiting time of two weeks versus six.

Level of DetailTermDetail Level, Model Resolution

The degree of granularity with which a decision-analytic model represents disease states, events, and population characteristics.