Ebel's Method
Using Ebel’s method, each item is rated according to two standards: difficulty and importance.
The difficulty of an item is characterized as easy, medium, or difficult, while the importance is characterized as acceptable, important, or essential. After the panel of subject matter experts agrees on the definition of a minimally competent candidate, a determination is made as to the percentage of items in each of the nine categories such a candidate would answer correctly. This percentage is multiplied in each of the nine categories by the number of items it contains. The passing score is set by averaging the category scores.
Here is a type of grid used when applying Ebel’s Method.
Here is a populated table that shows the percentage of items in each of the nine categories a borderline candidate would answer correctly:
Here is an illustration of how the percentage is multiplied in each of the 9 categories by the number of items it contains:
Modified Ebel's Method
A modified Ebel’s method is also available.
A simplified version of the Ebel method asks subject matter experts to rate items only according to importance, categorizing them as essential, important, or indicated. After defining a minimally competent candidate, SMEs then assess how many items in each category such a candidate should be expected to answer correctly. The passing score is established by averaged the ratings across the three categories.