Use the Differencing Specification window to specify the list of differencing lags d=(lag, …, lag) in a factored ARIMA model. To specify a first difference, add the value 1 (d=(1)). To specify a second difference (difference twice at lag 1), add the value 1 again (d=(1,1)). For first differencing at lags 1 and 12, use the values 1 and 12 (d=(1,12)).