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IT systems availability targets

Statistics on the availability performance of key Australian Taxation Office (ATO) IT services.

Last updated 15 March 2021

One of our corporate priorities is to improve the availability and reliability of our IT systems to the community. As part of this strategy we developed service availability targets for our systems and committed to make available to the community our performance against these targets.

The availability targets were set to provide a balance between community expectations of a digital service or agency and the investment required to deliver these service levels. They are intentionally aspirational and deliberately ambitious, giving us a high standard to work towards.

We use industry recognised methodology to determine and measure the availability, and while our external facing systems are generally highly available, we are investing in a plan of IT system improvements to continually improve the client experience.

These improvements will roll out as part of a multi-year program and we expect to see incremental progress as our digital services scale to meet the growing use.

Availability targets

We use industry recognised methodology to ensure consistency, comparability and best practice in our methods. The targets are classified into two categories determined by business needs and community use.

Targets and their corresponding measures

Availability target

Performance measures

High availability

  • 99.95% availability
  • High level of resilience with automated recovery
  • Numbers of scheduled maintenance windows are minimal and proactively managed with community engagement

Extended availability

  • 99.5% availability
  • Improved level of resilience with semi-automated recovery
  • To be taken offline for maintenance in agreed windows

Calculating monthly percentages

To measure availability of our external facing systems we use industry recognised methodology. Preventative, planned maintenance time is not included in the availability calculations. We do however schedule this necessary work outside of business days and hours and lodgment dates wherever possible.

Monthly percentage

The monthly percentage is based on the amount of time each system is available during a calendar month. It is calculated as a percentage of the actual available hours compared to the planned available hours.

Planned available hours

This is the availability target minus the planned maintenance hours. This figure represents the number of hours the systems should be available to users in that month.

Planned maintenance hours

Systems are taken offline to perform necessary maintenance. These are communicated and advised in advance (via, emails, social media). The planned maintenance hours are the number of hours within the availability targets where the system is offline due to planned maintenance.

Total system issue hours

Occasionally incidents result in systems being unavailable. Total system issue hours are the number of hours within the availability targets where a system may be offline due to an unplanned incident.

Actual available hours

These are the number of hours within the availability targets for each system minus any total system issue hours that may have occurred in the month.

Find out about:

IT systems availability figures for the 2022–23 financial year.

IT systems availability figures for the 2021–22 financial year.