‹ BackHN Continuity

Thread

Plunging test scores are a slow-moving catastrophe

207 points · 414 comments · vinni2

  1. vincent-uden · · focus · HN ↗
    This very much echoes the region of critical slowing down present in a dynamical system after its equilibrium states have disappeared due to a change in the system (a bifurcation).
    1. andsoitis · · focus · HN ↗
      restate in simple language please?
      1. vincent-uden · · focus · HN ↗
        I wanted to relate the result to well known phenomena in Dynamical systems. The value of the comment is in that relationship. But I guess I can try.

        After a saddle-node bifurcation (for example) a system is left with a region of critical slowing down. It can be thought of as the ghost of the fix point that used to exist in that region. Thus observing local phenomena in the system can make it look like the system is still stable while in reality it isn't.

        I guess the most famous example of this is global warning. As our emissions of greenhouse gases increased during the industrial revolution, the environment still seemed stable. But in reality we had already deleted the stable point around with our planets temperature oscillated.

        1. Lerc · · focus · HN ↗
          Where is the slowing down? What causes it?

          I can see there a compounding drift from the stable point that is not initially apparent because the compounding values have not yet grown sufficiently to be meaningful. It is still an increase in drift

          Slowing down implies a decrease though, what does that represent then?

          1. vincent-uden · · focus · HN ↗
            I think we see the slowing down primarily in hiring right?
Open on Hacker News to reply ↗

Unofficial Hacker News client; not affiliated with Y Combinator.