1 - Immediate risk life and death scenario: robberies, assaults with or without weapons, abductions, motor vehicle accidents with injuries, domestic violence, etc

2 - Significant risk to public safety or property, with crime in progress/good chance of catching perpetrator: drunk driving, break and enters in progress, escalated situations of violence that aren't yet extreme, etc

3 - Non-urgent but needing attendance police matters that may be able to afford to wait a bit for a response: shoplifters in custody, removal of unwanted people from business establishments, harassment without suspect on scene, general disturbances, general assistance, some property crime. A lot fits under here

4 - Not urgent, can wait a long time for response or telephone response only: historical break and enter, vehicle break ins, fraud/scams, lost and found property, etc

source: I won't say what I do or where I work but I will say I work directly with these policies in some capacity and have extensive knowledge of them.