Year-on-Year (YOY)

Year-on-Year comparisons are used to measure the difference in a data series between the same two time periods. Comparing the current Financial Year to one or more of the previous Financial Years.

Year-on-Year (YoY) is a frequently used calculation to compare two or more data series that can be measured on an annual basis. The time period for the calculation must be stated as it is essential that it is over the same time period. For example, the phrase used could be 1st Quarter YoY Sales Growth. Business conditions for companies in the Retail Sector can be very seasonal. Comparing the same period will assist in mitigating seasonal influences. The data series used in YoY comparisons could be performance data, return on investment or a growth rate, for example Sales. Thus, a YoY comparison could determine if the current year’s performance data or growth rate has improved, remains unchanged, or worsened compared to previous years’ data. Then the question is why, what’s going on?