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Two types of thresholds exist.

  • Type One
    • Values below the threshold are good, and values above the threshold are bad.
  • Type Two
    • Values above the threshold are good, and values below the threshold are bad.

Is there a good word to describe the orientation or direction of a threshold? The best I have been able to come up with is "lower is better" for Type One, and "higher is better" for Type Two.

Some definitions imply that a threshold is something to be exceeded. Others definitions describe it only as a point to be crossed. What I want to describe is the direction to be crossed. I'm also open to suggestions for a word other than threshold, for those who think that threshold is a poor word choice to describe something that can be bidirectional.

Used in a Program

public class Threshold 
{
    public static int thresholdValue;
    private boolean higherIsBetter; // Is there a more concise name for this?

    public static setThreshold

    public boolean crossesThreshold(int value) 
    {
        if (higherIsBetter)
            return value > thresholdValue;
        else
            return value < thresholdValue;
    }
}

Bidirectional Examples

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  • I'll have a think about a word for the directionality of a threshold in a generic sense, but as a start: a threshold where "above" is good, and "below" is bad, is a floor, whose opposite is a ceiling. – Dan Bron Oct 9 '14 at 15:35
  • The question "Is there a good word to describe the orientation or direction of a threshold?" does not make sense until you have another reference point. A threshold is simply a fixed point. – SrJoven Oct 9 '14 at 20:04
  • @SrJoven Use the points at the ends of the scale upon which the threshold lies as two additional reference points. For example, Bruce Banner has a threshold on a scale from "calm" to "angry". The percentages in my examples are on a scale of 0% to 100%. Hope that helps. – Rainbolt Oct 10 '14 at 13:38
  • No, Bruce banner has a scale from calm to angry. The point on that scale that turns him into the hulk is the threshold. One point. Nondirectional. Above is Hulk, below is human. – SrJoven Oct 10 '14 at 14:54
  • 1
    As another example, take the freezing point of water. It doesn't have a direction. It has a value. 32 degrees F/0 degrees C. Above the threshold is liquid. Below the threshold is solid. But it, itself, has no direction. If you want to ask for "A term which describes that a threshold is below a current point" ask that question. This is different from the question "A term which describes that a threshold is above a current point" and yet you want a term like delta vector which describes that a point is directionally distant from current point, but doesn't in itself specify which direction. – SrJoven Oct 10 '14 at 14:59
2

Industrial Statistical Process Control (SPC) has a technique involving upper limits and lower limits to track the parameters of a process. There are three kinds of parameters

  1. has single-ended upper limit
  2. has single-ended lower limit
  3. is dual-ended, to operate within a range constrained by upper and lower limits.

Before the parameter even reaches either limits, there are alarm ranges

  • upper alarm range
  • lower alarm range

with their respective thresholds.

By having an upper threshold or upper limit, it would be natural logic that it is lower the better. Conversely having a lower threshold or limit, natural logic would assume higher the better.

Though beyond the scope of this question, it might be helpful to your software strategy, to understand the various algorithms or criteria alarm ranges are triggered to preempt a process parameter from hitting its limits thresholds. Read up on Control Charts of Statistical Quality Control aka Statistical Process Control.

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