Is it necessary to recalculate all time series when new data become available each year?
Answer Yes. Adding data of a new year may lead to changes in the computed indices of previous years. Indices are based on a statistical model for the entire time series and adding new data to the model may affect the estimated parameters for all years. Thatīs why new indices for all years are calculated each year. Usually, however, changes in indices of earlier years are small and within the confidence intervals calculated in earlier runs.