Adjustments of forecasts to ensure that the whole will equal the sum of its parts. Such adjustments are needed because forecasting the whole will produce a different forecast than forecasting the parts and summing them. The forecaster can draw upon at least three approaches: (a) the bottom-up approach: summing model-based forecasts for each subgroup at the lowest level of the hierarchy to obtain forecasts for all group totals. (b) The top-down approach: allocating forecasts for each group total to subgroups. (c) The middle-out approach: In a hierarchy with three or more levels – for example, brand, flavor, package size – creating model-based forecasts for a middle-level (flavor in this case) and then reconciling higher levels (brand) using the bottom-up approach and the lower levels (package size) using the top-down approach.