step_function.rb

def step(min: 1, comp: 20)
  return 0 if min == comp

  (1 - (min - comp).abs / (min - comp).to_f) / 2
end

I use this in monitors all the time to remove flappy, low volume metrics.

For instance... an error rate monitor might

a = errors count
b = total count
error_percent = a / b
step = (1 - abs(1 - b) / (1 - b)) / 2
error_percent * step

You can compare against the errors or the total in this case.

If b < 1, the step evaluates to 0, otherwise 1.

Datadog now has cutoff_min which is wayyyyyyy easier to use