When building a chart in Data Buffet, you must choose which date range (horizontal axis) to plot. As of May 2010, there are five ways to do so, labeled:
- Start and end dates
- Start date
- Entire series
- Previous periods
- From end of history (new!)
The new mode is useful when charting forecasted data. Our forecast horizon is 30 years, but you may want to focus on recent history and the near future -- e.g., the past five years and upcoming three. In Data Buffet, each forecast series exposes a "last historical point" attribute (LHP) (or "historical end date"), where T is the last period based entirely on reported data, and T+1 is the first projected period.
To employ this chart feature, pick a forecast series first. You may then pick additional forecast and/or historical series. If you pick a historical series first, its last point will be used. In the date range chooser at the upper-right corner of the chart, select this mode, then specify the "pre" and "post" number of periods relative to the LHP.
Please note: Due to varied update schedules, two forecast series may not have the same LHP; but they will be similar. Some of the specialized forecast databases do not expose an LHP attribute. Most, but not all, forecasts are quarterly.
The "last historical point," when available, is listed in the Mnemonic 411 Summary tab.
It is also available as an optional basket field. From the basket editor, pick Options » Fields » Data Values » Historical end dates.
You can apply different line styles (dashed, color) to the historical and projected portions of each forecast time series. From the list of series, pick More Options » Forecast Area » Style = Change Line Style.
You can shade the forecast portion of a chart. From the list of series, pick More Options » Forecast Area » Style = Color Background.