It relates to the volatility of the asset mix. The values are derived from the Market Assumptions underlying the plan. The market assumptions can be found in plan settings. Rather than stating the 'standard deviation' value for a 'portfolio'; we represent this information as a range of returns (the 'up' and 'down' values); specifically, we show the range of returns between +/- 2 Standard Deviations either side of the 'mean' (with 'mean' being the 'expected average' figure, of course):
Higher Volatility: An "up" value could be associated with a scenario where the asset class of interest is expected to exhibit higher volatility. This might mean a scenario with more significant variability in returns.
Lower Volatility: Conversely, a "down" value is associated with the scenario where the asset class is expected to exhibit lower volatility, indicating a more stable or predictable environment.
Example: Using the same example of the standard deviation of stock returns, the "down" value reflects a scenario where growth is expected to be less volatile.