The internal audit activity has adopted the balanced scorecard approach to assess its performance According...

When using the balanced scorecard approach to assess the performance of the internal audit activity, a key performance indicator relevant to the audit client is the percentage of recommendations implemented by the corrective action date. This KPI measures the effectiveness and impact of the audit activity by tracking how well the audit recommendations are being acted upon within the agreed-upon timeframe. It reflects the responsiveness and commitment of the organization to address identified issues and improve its control environment, which is directly relevant to the interests and concerns of the audit clients.

The Institute of Internal Auditors (IIA) Practice Guide: "Measuring Internal Audit Performance"

Kaplan, R.S. & Norton, D.P. (1996). "The Balanced Scorecard: Translating Strategy into Action"