Adding Functions to reports
Optionally, you can apply mathematical functions to numerical event data or ratios for the Focus range and display the results in the same chart as the instance data. Using these functions, such as same day average, average, minimum, and maximum, you can make immediate comparisons of instance data against data across the function period range.
To the same metric, you can add multiple functions or duplicates of the same function, with different date ranges. If multiple functions are used for the same metric, the first function must have a value, or none of the functions are displayed.
Functions can be added for any event or ratio if no dimensions are present. If the Hour of Day, Day and Hour, or Day dimension is added to the chart, you must explicitly add a time-based dimension to the chart to enable the adding of functions.
Functions cannot be used in the same report as Top N filtering.
If you add multiple ratios with functions to a report, you cannot use non-calendar dimensions in it.
Add Function steps
Adding functions to a report involves:
- To display the Add Function menu, you must remove the Compare range from the report. Functions are applied to Focus data over the specified period range. Functions can be applied to the Focus range data only. They may not be added if a Compare range is defined for the report.
- To add a function, select it from the Add Function submenu in the drop-down menu for the event or ratio.
- After you add the function, you can configure it, including changing the range of the function. .
Function types
The following functions are available to apply to Focus data for events or ratios.
- These function types are compatible with the following dimensions: Day, Day and Hour, and Hour of Day (for single date Focus ranges). These functions cannot be used with other time dimensions.
- If no date range dimension is explicitly included, the date interval is automatically calculated to display in the most legible output. For example, for date intervals larger than 28 days, the date interval is set to Month, and functions cannot be applied.
| Function | Description | Default Period Range |
|---|---|---|
| Previous Days Average | Average value of the values over the number of preceding days that are specified by the period range | 4 data points (4 days) |
| Same Day of Week Average | Computes a rolling average of the data for the same day over the number of preceding weeks that are specified by the period range. | 7 data points (7 days) |
| Same Day of Week Minimum | Minimum value of the values for the same day over the number of preceding weeks that are specified by the period range | 4 data points (4 weeks) |
| Same Day of Week Maximum | Maximum value of the values for the same day over the number of preceding weeks that are specified by the period range | 4 data points (4 weeks) |
When a function is added, it is listed by name under the event or ratio to which it is applied. The chart is updated to include the function output next the focus period data.
- You can add multiple functions of different types to the same event or ratio. You can not add multiple functions of the same type to the same item.
- You can change the type of charting for the function in the drop-down menu.
- Each function is also added as a column in the detail table.
You can configure aspects of the display of the function data from its drop-down menu. Specifically, you can configure the range of the reporting period for the function data.
Function period ranges
The period range for the function indicates the number of data points to use in the calculation. You can select one of the predefined values or enter a custom value for this period.
Depending on the type of function, how the configured number of data points applies to the Focus data can vary.
When a function is added, no check is made to see whether data is available for all data points required to fill the function period range. Reported values can be influenced by incomplete data. For example, if only seven days of data exist for a 28-day period, then the average value calculations are skewed downward. Minimum and maximum values can not capture the true values over the period.
For averaging functions, the function period range must be at least 3. The upper limit in days to the function range is defined by the number of days of daily reporting data that are retained (Reporting Data (daily)-Days Retain). This limit does not factor the date when Tealeaf® was installed; it is possible to specify a function period that includes dates before Tealeaf was installed.
To verify the presence of data over the function period, configure the Focus range for each event to which you are adding a function to be a period as long as the function period range.