Introducing new forecasting capabilities in Power View for Office 365

Today at the PASS Business Analytics conference we announced the availability of new forecasting capabilities for Power View in Office 365. In Power View, you can now apply predictive forecasting, and hindcasting, when visualizing and exploring your data. Forecasting in Power View utilizes built-in predictive forecasting models using exponential smoothing to automatically detect seasonality in the data to provide forecast results from a series of data. Explore forecast results by adjusting the desired confidence interval or by adjusting outlier data to see how they affect results. You can also hindcast to see how Power View would have predicted the present and recent past based on older data.

The best data for forecasting is time series data or uniformly increasing whole numbers. The line chart has to have only one line. Multiple-line charts won’t work, even if all but one line is filtered out. See more things to keep in mind about forecasting.

You can evaluate how accurate a prediction is by combining these techniques:

• Vary the confidence interval to understand expected variance in future forecast results
• Try hindcast to see how the algorithm performs in practice on your historical data.

The forecasting in Power View performs advanced statistical analysis of your data to generate forecasts that incorporate trends and seasonal factors. Learn more about these methods and how to customize your forecasts to get the best results.

Try the new forecasting capabilities of Power View today on your own data or with the sample report available as part of the Power BI report samples. To view your own data, upload a workbook with a Power View time series line chart to Power BI for Office 365.

Open the file in Power BI and switch to Power View in HTML 5 (choose Try the HTML5 version of Power View  in the lower-right corner). 

Then click the forecast arrow or drag the forecast dot in the line chart, and you’ll see the forecasting options appear in the Analysis pane to the right of your report, as seen in the following image. 

Hindcasting shows how the forecast would've predicted the recent past, from the vantage point of the past.

1. Now that you've got a forecast, you also see an arrow pointing left, at the beginning of the forecast. That’s the hindcast arrow.
2. Click the hindcast arrow or drag the hindcast dot to the left to see how it would've predicted current values, if you had asked in the past.

To undo forecasting, click the arrow to the left of the forecast dot

Things to keep in mind about hindcasting

• For hindcasting to work, the line chart needs a minimum of seasonality periods.
• Filtering can impact hindcasting.
• Hindcasting is really a new and separate forecast, with its own seasonality and values in the Analysis area.

Adjust your forecast

The following capabilities are available to help you adjust your forecast:

Power View automatically detects what appears to be the seasonality of the data – in other words, a complete cycle of peaks and dips. For example, if you have high summer sales and low winter sales year over year, and you have daily data points, then the seasonality may be 365 - 365 data points in the one-year data cycle. You can override automatic seasonality detection.

1. Start a forecast by dragging the forecast handle in a line chart.
2. The Analysis Pane will automatically pop up on your right hand side. Can’t find it? Look for Analysis in the upper-right corner.
3. In the Analysis area, manually set the seasonality to none, 2, 3, 4, 5, 6, 7, 12, 24, 52, or 365.

   Tip : Seasonality works best if the chart has at least four times more values than the data cycle. For example, if you set the seasonality to 52, you’d want to have at least 4 times 52, or 208, values in the time series axis of your chart.

The confidence interval shows visually how reliable the forecast is. Standard deviation is the setting for the confidence interval of forecast results.

1. Start a forecast by dragging the forecast handle in a line chart.
2. The Analysis Pane will automatically pop up on your right hand side. Can’t find it? Look for Analysis in the upper-right corner.
3. In the Analysis  pane, adjust Standard Deviation to show values with a standard deviation of 0, 1, 2, or 3..