Incident severity and downtime trend analysis is the most important result to report to the CIO to measure progress in improving system availability to mitigate IT risk to the business, because it directly reflects the impact and frequency of system failures or disruptions on the business operations, processes, and functions. By analyzing the severity and duration of incidents over time, the CIO can evaluate the effectiveness of the IT risk management and system availability strategies, and identify any gaps, issues, or opportunities for improvement. Incident severity and downtime trend analysis can also help the CIO to communicate the value and performance of the IT risk management and system availability initiatives to the business stakeholders, and justify any further investment or action required to achieve the desired outcomes.

The other options are not as important as incident severity and downtime trend analysis, because they are either too indirect or too subjective to measure progress in improving system availability to mitigate IT risk to the business. Probability and severity of each IT risk is a useful input for IT risk management, but it does not necessarily reflect the actual occurrence or impact of system failures or disruptions on the business1. Financial losses and bad press releases are possible consequences of system failures or disruptions, but they may not capture the full extent or root causes of the IT risk to the business2. Customer and stakeholder complaints over time are indicators of customer satisfaction and loyalty, but they may not be reliable or consistent measures of system availability or IT risk to the business