Question

When already given tool values, how do I create cut-off values from scratch for a screening tool?

Answer 1

Suppose I have a Questionnaire for a Stress assessment that contains 30 questions, each question has 5 answers (0- no stress, 1-mild stress, 2- moderate , 3-High stress, 4- Severe stress). The Total score of the 30 question varies from 0 - 120.

The cut off score usually is defined by the original author for the tool.

If you develop the tool, then you have to do pilot testing and validate it by a group of expert in the field who can decide the cut off point.

However, most of the inferential statistics assumptions recommend the Dependent Variable to be measured on a continuous scale, not a dichotomy

Make cutoff points using a calculator (Maximum- Minimum / n). How? In case of a five-point Likert scale, you may, for example, have assigned the value (1) for Strongly Disagree, (2) Slightly Disagree, (3) Neutral, (4) Slightly Agree, (5) Strongly Agree.

Do the math for the three categories (Low, Mid & High). How? Just add up the score of your interval value to the three category, as in the following:

Low (1 - 2.339),

Mid (2.34 - 3.669)

High (3.67 - 5).