In this article
As a Creator (Project Owner), you can flag a measure or measure group as a target (Norm), against which significant differences can be calculated. The option is available in the design menu under the flags section.
1. Norm Flags
There are three Norm flags available in Harmoni. The flag to use depends on the nature of your target.
- Proportional Norm - use this flag if your target is between the values of 0 and 1. This can also be referred to as Ratio. For example, Brand Link Ratio.
- Percentage Norm - use this flag for percentage-related values 0-100%, for example, Campaign Recall.
- Value Norm - use this flag for exact values, for example, sales and profits.
2. Norms In Analysis
In an analysis with a Norm, Harmoni will use the Norm Significance Test rather than the standard chi-squared test/t-test calculations for single reference difference calculations.
Significant differences are represented using green and red
arrows.
Harmoni defaults to the standard significance test calculations (SIG) between regular cells if a standard column/row is set as a reference. The Norm (SIG) calculation is ONLY used between the reference cells and the test Norm cells.
In an analysis with Multiple reference significant differences (M-SIG), the Norm significance test will not apply and will be excluded from calculations at this stage.
3. Statistical Testing using Norms
When a measure or measure group is flagged as a Norm item, Harmoni performs statistical testing against this target. Harmoni uses the flag to determine the significance test to use.
Proportions/Percentages against a Norm
Harmoni uses one sample proportion test.
One-sample proportion test is used to test whether a sample proportion is statistically different from a hypothesized proportion. The hypothesized proportion is often called a norm or a target and is a given constant value.
For proportional norm, we add Yate’s Continuity Correction. In short, Yate's Continuity Correction adjusts the number passed to the NORM significance test a little bit, to improve the accuracy of the test. However, it makes the calculation more conservative and leads to slightly reduced statistical power
Value against a Norm
Harmoni uses a one-sample t-test.
The one-sample t-test assesses whether the mean of a sample is statistically different from a hypothesized value, for example, a specified norm or target. You would use this test for measures or averages.
Bases Used for Testing
- If the Effective Base is enabled, the effective base from the Total row/column is used as the sample size for all Norm sig calculations (Ratio, Percentage, Value).
- If the Effective Base is OFF, the Unweighted Count (U123) from the Total row/column is used as the sample size for all Norm sig calculations (Ratio, Percentage, Value).
Learn more about effective base.
Where to from here?
Learn more about statistical testing:
- Statistical Significance in Harmoni (SIG)
- Multi-Reference Statistical Significance in Harmoni (M-SIG)
- Effective Base