Taylor Series Expansion
A Taylor series expansion approximates a function near a point by a polynomial built from its derivatives, used in health economics for the delta method.
Encyclopaedia
Explore comprehensive, evidence-informed explanations of key health economics concepts, including their development, application and relationships to other concepts. Published entries are validated through human expert review.
Concepts, entries and ontology terms
A concept page is a published entry on the wiki. Some concepts also have a full encyclopaedia article. The Health Economics Ontology (HEO) holds every concept, including dictionary terms without an article, so it is larger than the list of published pages. The knowledge graph shows how concepts relate to each other.
Technical Efficiency
Technical efficiency is producing health care with the fewest inputs that best practice allows, or the most output from given inputs, ignoring prices.
Technological Externality
A technological externality is an externality that changes another person's health, wellbeing or output directly, not through prices, as infection does.
Theil Index Health
The Theil index in health is an entropy-based measure of relative inequality in a health outcome that splits exactly into parts between and within groups.
Theory of the Second Best
The theory of the second best is a welfare theorem that if one efficiency condition fails, as in health care, meeting the others may not raise welfare.
Threshold Analysis
Threshold analysis finds the switching value, the level an uncertain input must reach for the preferred option in a health economic model to change.
Time Dependency
The property of a risk, effect, cost, utility or other model input changing according to a specified time scale, such as attained age or time since an event.
Time Horizon
The time horizon is the period over which an economic evaluation counts costs and health effects, set long enough to capture all important differences.
Time Preference
Time preference is the preference for benefits sooner and costs later; in health economics it is one reason future costs and QALYs are discounted.
Time Value of Money
The time value of money is the principle that money held now is worth more than the same sum later, the reason economic evaluations discount future costs.
Time-Driven Activity-Based Costing
Time-driven activity-based costing (TDABC) costs health care by multiplying each resource's cost per minute of capacity by the minutes a patient uses.
Time-Homogeneous Model
A time-homogeneous model is a Markov model whose transition probabilities are the same in every cycle, so health state risks never change with age or time.
Time-Inhomogeneous Model
A time-inhomogeneous model is a Markov model whose transition probabilities can change between cycles, so a risk such as death can rise as the cohort ages.
Time-to-Event
Time-to-event data record the time until an event such as death or progression, with some times censored, and supply survival inputs to economic models.
Time-Varying Covariate
A time-varying covariate is a predictor in a survival model, such as drug use or a biomarker level, whose value is updated during follow-up.
Time-Varying Hazard
A time-varying hazard is an event rate among people still at risk that rises, falls or turns over follow-up, as in many health economic survival models.
Tolerance Interval
A tolerance interval is a range that, with stated confidence, encloses at least a set share of individual values in a population, such as patient costs.
Top-Down Costing
A costing approach that starts with aggregate costs and allocates them to services, activities or patients using documented shares and output counts.
Tornado Diagram
A tornado diagram is a bar chart of one-way sensitivity results in a cost-effectiveness model, ranking inputs so the widest swing in the result is on top.
Total Effect Index
The total effect index is the share of a health economic model output's variance due to one uncertain input, counting its main effect and all interactions.