When data are provided quarterly, is the percent change for the year equal to the average of the percent changes for the four quarters?
The percent change for the year should closely approximate the average of that year’s four quarterly percent changes from the corresponding quarter of the preceding year. Because the percent change values presented in the official data are rounded to one decimal point, and because of minor variations in the year-to-year values used for seasonal adjustment of the quarterly data, results of a calculation based on press release data will reflect a small difference between the percent change for the year and the average of the quarterly percent changes from the preceding quarter a year ago. The percent change for the year is NOT equal to the average of that year’s four quarterly percent changes from the previous quarter of the same year. The quarterly percent changes calculated from the previous quarter of the same year do not capture information on the year-to-year movement of the index number.
