What is the MOST important consideration when selecting key performance indicators (KPIs) for control monitoring?

The most important consideration when selecting KPIs for control monitoring is that the source information is consistently available, meaning that it can be obtained regularly, reliably, and timely from the same or equivalent data sources. This ensures that the KPIs can measure the performance of the controls over time and across different units or functions, and provide meaningful and comparable results. Source information that is acquired at stable cost, tailored by removing outliers, or readily quantifiable are also desirable, but not as essential as consistency.