4.3 Quarterly change

To measure quarterly change, the index value for a quarter is compared with the value for the previous quarter. The figures are calculated in the same way as for monthly change. To calculate quarterly changes from one-month figures, you will need first to calculate the arithmetic mean of the monthly index values for the quarter in question.

The example below shows the change in the consumer price index from the fourth quarter of 2002 to the first quarter of 2003:

CPI 2000=100 index values for 2000-2003

Month	2001	2002	2003
January	100.89	103.19	104.59
February	101.51	103.35	105.28
March	102.06	103.90	105.57
April	102.53	104.33	105.44
May	103.21	104.56	105.31
June	103.20	104.34	105.19
July	102.43	104.15	104.64
August	102.75	104.15	104.78
September	103.49	104.53	105.21
October	103.26	104.80	105.10
November	102.80	104.47	105.00
December	102.76	104.46	105.09