pension plan time horizon

I know the book says that generally it’s long term if going concern and short if terminating plan.

I’ve seen in past exams that when the ratio of retired to active lives has increased, we say that the time horizon has decreased.

Based on this, if originally presented with a plan with a high ratio of retired to active lives, would you say the time horizon is long, short, or something like “Similar to most pension plans, this plan has a long time horizon because it is a going concern; however, the high ratio of retired to active lives is high and liquidity needed to fund retirees reduces the duration of the plan’s liabilities and decreases its time horizon.”

sounds ok to me . should get the idea across. but can cut it shorter .

high retired to active lives ratio significantly reduces the time horizon as liabilties are due earlier

Quick question on time horizon: What are the general limits for short/long/medium… In other words, is short < 5 years, Long > 15 years, anything in between medium? I am thinking mostly for the individual IPS when they give you the number of years. Can’t say I have seen anything called “medium term”, but if I get a 12 year time horizon on the exam I would be inclined to write that.