The best source of information for assessing the effectiveness of IT process monitoring is performance data. Performance data is a type of information that measures and reports on the results or outcomes of IT processes, such as availability, reliability, throughput, response time, or error rate. Performance data can help assess the effectiveness of IT process monitoring by providing quantitative and qualitative indicators of whether IT processes are meeting their objectives, standards, or expectations. The other options are not as good as performance data in assessing the effectiveness of IT process monitoring, as they do not provide direct or objective evidence of IT process results or outcomes. Real-time audit software is a type of tool that can help automate and facilitate audit activities, such as data collection, analysis, or reporting, but it does not provide information on IT process performance. Quality assurance (QA) reviews are a type of activity that can help evaluate and improve the quality of IT processes, products, or services, but they do not provide information on IT process performance. Participative management techniques are a type of method that can help involve and motivate IT staff in decision-making and problem-solving processes, but they do not provide information on IT process performance. References: CISA Review Manual (Digital Version), Chapter 3, Section 3.3