One of the key metrics surfaced in Noibu to help you prioritize an issue is Annual Revenue Loss (ARL) value. This number is an estimate of the revenue impact of leaving an issue unresolved for a full year. An issue's ARL may change as Noibu collects more data, but it's best to investigate and resolve issues with high ARL as soon as possible.

To estimate an issue's ARL, Noibu considers several metrics:

• The number of users impacted by the issue over the past 90 days. This refers to unique user sessions where the issue occurs, including sessions where the user successfully completed a transaction.
• The conversion drop-off rate due to the issue. This refers to the percentage of users that were unable to progress through the purchase journey, as compared to domain average.
  • For example, if the average conversion rate for a given step is 92.8%, but the conversion rate among users who encounter the issue is only 15.1%, then the conversion drop-off rate is: 92.8 – 15.1 = 77.7%
    
  • Note: Noibu only shows sessions lost (and therefore revenue loss) when the difference from domain average is greater than 10% for the On Site stage, and greater than 5% for the Added to Cart and Checkout Started stages.
• The average order value. You must configure this value manually for each domain in the Domains module.
• The number of days the error has been present, extrapolated to an annual basis.

Based on these data points, Noibu calculates ARL using the following formula:

• If the issue is 1 day old: ARL = 0
• If the issue is 2-14 days old:
  ARL = [users impacted] × [conversion drop-off rate] × [average order value] ÷ 14 × 365
• If the issue is 15+ days old:
  ARL = [users impacted] × [conversion drop-off rate] × [average order value] ÷ [days present] × 365

Other Calculations

The Funnel Statistics table also reports the Sessions Lost and Transactions Lost at each stage. These totals are calculated as follows:

• Sessions Lost = Total Sessions × [conversion drop-off rate]

• Transactions Lost = Sessions Lost × Domain Average Conversion Rates for Remaining Steps in the Funnel

Note: Transactions Lost and Sessions Lost are only distinct values at the On Site and Add to Cart steps. At later steps, Transactions Lost accounts for organic drop-off due to errors experienced at earlier steps.

You can view many of the metrics used to calculate an issue's ARL in the Funnel Impact section in the issue's Overview tab.