A collection of averages calculated for a group of data shown over a certain number of (usually) equal time periods. Calculating the trend / moving average involves the following steps: 1) Selecting a number of time periods for calculating the average. NB This should be done on a rational basis, eg if the data consists of the quarters of a year then four quarters should be used to calculate the average. Alternatively, if the data consists of years and there is an obvious peak every third year, then three years should be used. 2) Totalling the first available set of values up to the number of the time periods selected and calculating the average, eg Quarter 1 + 2 + 3 + 4 divided by 4. 3) Repeating the process for the set of data, eg Yr 1 Qtr 2 + 3 + 4 + Yr 2 Qtr 1, and so on.