Vísitalan
Vísitalan is a statistical concept used to express the relative change in a variable over time. In its standard form, a vísitala (index number) compares the value of a measurement in a given period to that in a base period, and is typically scaled so the base period has a value of 100 (or 1). The resulting figure shows how much the quantity has increased or decreased since the base period.
Calculation can be simple or weighted. A simple index uses the ratio of current value to base
Vísitalan has broad applications. It is used to track inflation through price indices such as the consumer
In Iceland, as in many countries, statistical agencies publish vísitölur. The term vísitala is widely used for
Historically, index numbers were developed in the 19th and early 20th centuries to provide a compact summary