To verify whether your organization has effectively implemented the requirements of ISO 9001:2015 section 4.4.1 part (c), you need to conduct a thorough evaluation of how you've determined and applied criteria and methods for process control and effectiveness. Start by reviewing documentation related to the performance criteria you’ve set for each of your processes. Check whether these criteria are clearly defined and directly aligned with your organization's quality objectives. Each process should have specific, measurable key performance indicators (KPIs) that accurately reflect its effectiveness.

Next, examine how these KPIs are being monitored. Verify that there are established methods for tracking process performance, such as periodic audits, statistical process controls, or automated monitoring tools. Ensure these methods are robust and consistently applied, providing reliable and timely data. It's important that the monitoring process captures data that can be effectively analyzed to assess process performance.

Furthermore, evaluate the mechanisms in place for responding to the data collected through these monitoring methods. Confirm that there is a formalized approach for conducting root cause analysis, implementing corrective actions, and reviewing outcomes when performance criteria deviate from expected standards. This should include documentation of corrective and preventive actions taken, as well as evidence that these actions have been assessed for effectiveness in resolving the underlying issues.

Finally, assess whether there is evidence of continual improvement based on the monitoring data. Look for regular reviews of process performance metrics and documented improvements or adjustments to the criteria or processes as a result. This demonstrates an active commitment to optimizing processes and maintaining an effective quality management system. Through this verification process, you can ensure that your organization's procedures for determining and applying criteria and methods for process control are not only established but are also functional and effective in driving quality improvements in line with ISO 9001:2015 standards.