Time-Based Variance

About the narrative

Details covered in the analysis

The length of the narrative and the level of detail the narrative contains depend on which Narrative length narrative option is selected.

For example, when Important things is selected, variance analysis of the measure is performed based on a threshold parameter, the value of which is selected by the user to be applied across all levels of drilldown. When Summary is selected, only the main driver is described. When Tell me everything is selected, all drivers and offsets are described.

Two types of thresholds are supported: Top and Coverage. See Narrative options for details.

The narrative includes some or all of the following:

  • an introductory section summarizing the key trends, drivers, and offsets for the measure (e.g. Profit). For example:

  • for the highest-priority dimension (e.g. Product), a section for each instance of that dimension (e.g. Nutrali), drilled down by up to two other dimensions (e.g. Segment and Country), which highlights the most significant insights. For example:



    The order of drilldown is determined by the order of dimensions set in Step 2 of the NLG Apps wizard: Data configuration.



Data requirements

All NLG Apps have the same data requirements for supported formats and field names. See NLG Apps Data requirements for details.

In addition, each app has specific data requirements:

If your data selection and configuration do not meet the specific requirements for a particular app, the app is disabled in the wizard and a warning message is displayed:


Dimensions and measures

This app can analyze:

  • one time dimension, up to three non-time dimensions, and one measure.

Minimum requirement: one time dimension and one measure.


The time dimension must be one of the following:

  • Date

  • Month

  • Quarter

  • Year

The Entity Type attribute for time dimensions must be set to DateTime in Step 2 of the wizard.


Aggregation and entity types

Not all combinations of aggregation and entity types are supported for measures. The Time-Based Variance app can analyze the following combinations:



Entity types and other data attributes are set in Step 2 of the wizard.



Narrative options

The following fields are available to configure in Step 3 of the NLG Apps wizard: Narrative options.





Select a time period to analyze. The time dimensions in your data selection must include the period you select here — either as a Date field, or as a Month, Quarter, or Year field.

Default: Month



Specify how you would like measures to be compared (e.g. Latest vs. earliest).

Default: Latest vs. previous


Entity Selection

Top: Limit the number of drivers and offsets described in your narrative to the top N contributors (e.g. “The top three performing regions were…”).

Default: 1.

Coverage: Report on only those drivers and offsets that contributed to a certain percentage of the variance.

Default: 50%


This option applies only when Summary and Important things are selected in the Narrative length field.


Narrative length

Summary: produces a narrative of filtered facts in a more concise way than the Important things option.

Important things: produces a narrative of filtered facts based on Arria's ranking algorithm.

Tell me everything: produces a narrative that includes every fact extracted from your data by Arria's algorithms.

Default: Important things