Pharmaceutical Benefits Advisory Committee

Glossary of I and L Terms

Glossary to accompany the Guidelines for the Pharmaceutical Industry on Preparation of Submissions to the PBAC

Important (see clinically important)
 

Incidence (compare with prevalence)

The number of new events (eg new cases of a disease) in a defined population within a specified period of time.

 

Incremental analysis

A measure of how much extra a proposed therapy costs to produce an extra unit of outcome compared to an available alternative therapy (or management without a therapy) for a specified indication. It is calculated by dividing the difference in the net costs for the two alternatives by the difference in their net outcomes.

 

Incremental benefit

The absolute difference between the benefits of alternative management strategies of the same disease or disorder.

 

Incremental cost

The absolute difference between the costs of alternative management strategies of the same disease or disorder.

 

Indication

The disease or disorder which is the reason for commencing therapy. On the PBS, the indication can be restricted to a defined sub-group of patients with the disease or disorder.

 

Indirect benefit

The value of an increase in an individual's productivity as a result of therapy.

 

Indirect cost

The value of a decrease in an individual's productivity as a result of disease or therapy.

 

Indirect outcome (see Appendix F, see also human capital and friction methods)

The value of a change in an individual's productivity as a result of therapy.

 

Input (see also resource)

A resource provided as part of managing a disease or disorder.

 

Instrument

A tool used to measure a variable, including any defined administrative procedures in its use and scoring instructions in its interpretation.

 

Intangible outcome

Any outcome that is incurred as a result of disease or therapy, but cannot be measured as changes in the provision of resources or as changes in labour productivity; may include concepts such as suffering and disability which may be implicitly valued by the PBAC (only if presented as a demonstrated outcome) or explicitly valued in a utility analysis or in a willingness to pay analysis.

 

Intention-to-treat (see Appendix B)

A principle of analysis which includes data from all subjects allocated to a specified therapy arm as representing that arm irrespective of whether they received or completed the prescribed regimen or whether they were followed for the full duration of the study/trial. This involves following-up subjects to contribute data and/or predetermining procedures to deal with missing data.

 

Intermediate outcome (see also surrogate outcome)

A variable that occurs in a causal pathway from a therapy or factor to the final outcome.

 

Internal validity (see also external validity, treatment effect)

A trial has internal validity if, apart from possible sampling error, the measured difference in outcomes can be attributed only to the different therapies assigned.

 

Interval data (see cardinal data)

 

ITT

intention-to-treat

 

 

Life-year

An outcome measure computed by multiplying the number of affected individuals by the number of years each individual is expected to live.

 

Lump (compare with pool)

An inappropriate statistical combination of data from several trials, eg taking the simple average of the means or of the proportions.