Survival analysis: hazard rates and half-lives

Does surviving a long time make something safer, or does every year carry the same risk regardless of age? This page gathers conjectures that borrow the statistical toolkit insurers and economists use to answer exactly that question for people and firms -- a hazard rate, meaning the odds of dying at a given age -- and apply it to monasteries, manuscripts, and whole writing media instead. Some processes are memoryless: a radioactive atom's odds of decaying in the next second never fall just because it has already lasted a long time. This lens asks whether a monastery's odds of closing, or a manuscript's odds of being lost, work the same way, with every physical writing medium carrying its own statistical half-life.

Memoryless monasteries tests the strong version of that claim directly -- that a monastery's survival really is memoryless, gaining no protection at all just from having lasted a long time. The universality class of survival and The fossil colophon is a stopwatch on the treadmill both ask whether the exact statistical shape of survival is universal across very different kinds of object, from manuscripts to dated colophons -- a scribe's own note of when and where a copy was made -- treated as a stopwatch on the copying treadmill. Dispersal hunts the painted tests whether paintings and illustrated pages specifically get dispersed and lost at a different rate than plain text, because they are worth more to cut out and sell separately.