The number of events impacting business processes due to delays in responding to risks is the best outcome measure to determine the effectiveness of IT risk management processes, because it reflects the actual consequences and losses that result from inadequate or ineffective risk management. Outcome measures are metrics that evaluate the results and benefits of a process or activity, rather than the inputs or outputs1. Outcome measures help to assess whether the process or activity is achieving its objectives and delivering value to the organization1. The number of events impacting business processes due to delays in responding to risks is an outcome measure that indicates how well the IT risk management processes are able to identify, analyze, evaluate, treat, monitor, and communicate IT risks in a timely and appropriate manner. A high number of such events would suggest that the IT risk management processes are not effective, and that they need to be improved or revised. A low number of such events would suggest that the IT risk management processes are effective, and that they are reducing the likelihood and impact of IT risks on the organization.

This is because a portfolio review is a process of evaluating the performance and value of IT investments in relation to the business objectives and strategy. A portfolio review can help to identify the alignment, contribution, and optimization of IT investments, as well as the risks, issues, and opportunities for improvement. A portfolio review can also help to communicate and demonstrate the value of IT to the board and other stakeholders, as well as to support decision-making and prioritization of IT resources.
Some of the sources that support this answer are:
1: This source explains the value of IT governance and how it can help to optimize risk and manage resources to support the organization's mission, goals, and objectives. It also discusses some of the governance enablers, such as principles, processes, and policies, that can help to align IT with the business context.
2: This source provides a research-based methodology to improve IT governance and drive business results. It suggests that conducting a portfolio review is one of the steps to redesign the governance framework and ensure that IT investments are aligned with the business strategy and deliver value.
3: This source defines IT portfolio management as a discipline that enables organizations to manage their IT investments as a collection of projects, programs, and services that contribute to the enterprise's strategic goals. It also describes some of the benefits of IT portfolio management, such as improving alignment, optimizing value, reducing risk, and enhancing transparency.

A new privacy regulation is a legal requirement that aims to protect the rights and interests of customers in relation to their personal data, especially in the event of a breach involving personally identifiable information (PII). A breach is an unauthorized or unlawful access, disclosure, alteration, or destruction of personal data that may compromise the confidentiality, integrity, or availability of the data1. A new privacy regulation may introduce new risk for an enterprise that collects, processes, stores, or transfers personal data of customers, such as legal, financial, reputational, or operational risk. Therefore, the IT risk management team's first course of action should be to determine if the new regulation introduces new risk for the enterprise, by assessing the scope, applicability, and impact of the regulation on the enterprise's data activities and practices. This can help the IT risk management team to identify and prioritize the gaps or issues that need to be addressed to comply with the regulation and to mitigate the potential risk23. Reference: What is a Data Breach? Definition & Examples. How to Manage Data Privacy Risks. Data Privacy Risk Management: A Guide for Businesses.

An updated business case for IT resourcing is a document that provides the rationale and justification for the proposed changes in the IT staff structure, such as the number, roles, skills, and costs of the IT personnel. An updated business case for IT resourcing should align with the IT strategy and objectives, as well as the business needs and expectations. An updated business case for IT resourcing should also include the benefits, risks, and impacts of the IT staff restructure, as well as the alternatives and recommendations12.
The other options are not as effective as an updated business case for IT resourcing to support an IT staff restructure. Established IT key performance indicators (KPIs) are measures that evaluate the performance and outcomes of the IT department, such as service quality, customer satisfaction, project delivery, and innovation. Established IT KPIs are important for monitoring and reporting the IT results and achievements, but they do not necessarily support an IT staff restructure, unless they are linked to the proposed changes in the IT staff structure3. IT staff training program requirements are specifications that define the learning needs and objectives of the IT personnel, such as skills development, knowledge enhancement, and career advancement. IT staff training program requirements are beneficial for improving the capabilities and competencies of the IT staff, but they do not directly support an IT staff restructure, unless they are aligned with the new roles and responsibilities of the IT personnel4. External IT staffing benchmarks are standards or best practices that compare the IT staff structure of other organizations or industries, such as staffing ratios, skill levels, or salary ranges. External IT staffing benchmarks are useful for assessing and improving the competitiveness and efficiency of the IT department, but they do not adequately support an IT staff restructure, unless they are customized and adapted to the specific context and situation of the organization5.
References: 1: How to Write a Business Case: 4 Steps to a Perfect Business Case Template - ProjectManager.
com 2: How to Write a Business Case # 4 Steps to a Perfect Business Case Template | Workfront 3: 18 Key Performance Indicator (KPI) Examples Defined - ClearPoint Strategy 4: How to Create an Effective Training Program: 8 Steps to Success - Convergence Training Blog 5: How to Benchmark Your Staffing Levels - HR Daily Advisor