2.1.3 Uses of index numbers

• Why are index numbers?

  The are easier to interpret than larger numbers
• What is an index number?

  A figure reflecting price or quantity compared with a base value
• What is the base index/year/period?

  100
• Examples of index numbers?

  Consumer price index, index of house prices, Human Development index and exchange rate index
• How do you calculate an index number from a value?


  (data value in year / base year value) x 100
• How do you calculate a figure from a base year value?

  (base year value / 100) x index of year
• How do you calculate a percentage change between years other than the base year?

  (index for Y / index for Z) x 100