code: private boolean pruneData(ThroughputDistribution priorStats, double forecast) {
          boolean prune = false;
  
          // if forecast tput is much greater or much smaller than priorStats, we suspect
          // priorStats is no longer relevant, so prune it
          double tputRatio = forecast / priorStats.getMovingAverage();
          if (tputRatio > tputRatioPruneLevel || tputRatio < (1 / tputRatioPruneLevel)) {
              prune = true;
          } else {
              // age & reliability (represented by standard deviation) check
              int age = controllerCycle - priorStats.getLastUpdate();
              double variability = (priorStats.getStddev() / priorStats.getMovingAverage());
              if (age * variability > dataAgePruneLevel)
                  prune = true;
          }
  
          return prune;
      }
docs: Evaluates a ThroughputDistribution for possible removal from the historical dataset.
  
  @param priorStats - ThroughputDistribution under evaluation
  @param forecast - expected throughput at the current poolSize
  @return - true if priorStats should be removed