Darkrenown said:
The opium trade even uses random = 2 to fire every once in a while, so you may want to use persistent = yes, offset = 30 and random = 25 to make it fire fairly often.
I've been studying the "Opium Trade" event in an attempt to see how persistent = yes works
One way for the event "Opium Trade" (12500) way for it to fire is by the random = 2 offset = 31 in the event itself.
Another way is a chain which fires it. This starts with event 6940 "Murder at Guangzhou". Assuming all the steps in the chain are triggered this results in command = { type=trigger which=12500 } in event "The Treaties of Beijing" (12516). That is the only explicit trigger for the "Opium Trade" event 12500
The final chain that effects event 12500 is the one started on 10th Dec 1838 by event 12501 "Lin Zexu". If you tell him to eliminate the trade then this starts a chain that ends with "China threatens British merchants in Guangzhou" (6939). This event contains command = { type = event_chance which = 12500 value = 100 } if option_a is chosen. This makes event 12500 fire automatically the next time it is checked.
If a different option is chosen, event for 12501, it results in an event similar to 12500 firing but actually isn't (event 12502 "High Commissioner Corrupted!" gives the same message to the UK though and has the same effects).
So there is one event chain that causes the event to fire once and only once. This means that any firings other than that must be because of the random trigger.
However if event 12500 is altered to random = 100 offest = 31 is fired once but never again in the next 12 months. Same for random = 50 and random = 25 and random = 12
Therefore if random > 12 then persistent = yes does not seem to fire an event several times.