Hi Felix:
The following topic in the NM TCP/IP documentation is an example that takes into account your question:
https://techdocs.broadcom.com/us/en/ca-mainframe-software/performance-and-storage/ca-netmaster-network-management-for-tcp-ip/12-2/implementing/configuring-ip-node-monitoring/example-define-an-ip-node-monitor-group.html
It does mention the Rate field, which is immediately below the Three Strike Alert field. The 3270 F1 help also provides more field level descriptions of the the Monitor Attribute panel.