I claim without proof (but appealing to what I know about competing risks theory) that it is not. Doesn’t make sense to me that you could measure a trend in a quantity that is statistically unidentified under dependent competing risks.

But the tension is that, let’s say you just invert that openings per filled opening measure. Then it’s filled openings per openings, a period rate. Fine to measure that since it’s basically just a constant hazard. (Although it assumes constant hazard of course)