4 ms·

Not really, they just fitted the cubic to log-deaths and exponentiated them again.

• CrazyStat 6y ago
  Cubic has to go to +infinity on either the right or left. Exponentiating doesn't help with that.
  • em500 6y ago
    exp(-infinity) = 0
    • CrazyStat 6y ago
      And exp(+infinity) = +infinity, so it has to go to +infinity on one side.
      • em500 6y ago
        Yes, on the right side, https://statmodeling.stat.columbia.edu/2020/05/16/what-a-difference-a-month-makes-polynomial-extrapolation-edition/ https://statmodeling.stat.columbia.edu/2020/05/16/what-a-dif... So in addition to log-exp to prevent projections going negative, they clipped the end date at 4 Aug to prevent it from going back up to +inf