Performance indicator

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Definition

quantitative or qualitative indicator, derived from one or several measures, agreed on beforehand, expressed as a percentage, index, rate or other value, which is monitored at regular or irregular intervals and can be compared to one or more criteria.

Example

mean speed per distance, number of overtaking maneouvres per hour

Source/Reference

generic (combination of different www sources and own)

Changed/Added by

VTI: KK

Why

initial

Comment

Hypotheses steer the selection of performance indicators, and the criteria against which those should be compared. Hypotheses are seen as questions that can be answered with the help of measurable performance indicators.

Criteria can be baseline, different experimental conditions, absolute values, etc. New PI or combinations can be developed during the course of the study. They will have to be validated in follow-up studies. A “denominator” is necessary for a performance indicator. A denominator makes a measure comparable (per time interval/per distance/in a certain location/…). Therefore “crash” or “near-crash” in themselves should rather be considered to be “events”, because they become comparable only when they get a denominator, like “number of crashes per year per 100.000 inhabitants”.