Setting the Passing Score in Audiology

In November 1996 the audiology exam sub-committee established a new method for determining the passing score for the audiology exam. The method, developed by Nedelsky in 1954, uses a test-centered approach, wherein subject matter experts (members of the exam committee) make judgments about the difficulty of test content. For each multiple choice question in the examination bank, the members of the exam committee consider each alternative to the correct answer and collectively judge whether an entry-level audiologist should reject that alternative as incorrect. Based on these Nedelsky judgements, each question receives Nedelsky value which is added into the passing score. In this way, the passing score is based on the judged degree of difficulty of each question.

For example, consider Example 1. below, a multiple choice question that has four response alternatives, with number 2. the correct answer. For the other three incorrect alternatives, the exam committee collectively decides that only number 4. should be rejected by an entry-level candidate. This leaves three choices (including the correct response) that an exam candidate could guess amongst, giving a chance value of 33%. For this item, the Nedelsky value would be 0.33.

Example 1.

Which of the following conditions places a child at risk for acquired sensorineural hearing loss?

1. Prenatal exposure to narcotics (would NOT be rejected)
2. Prenatal exposure to Cytomegalovirus infection (Correct Answer)
3. Prenatal asphyxia (would NOT be rejected)
4. Prenatal malnutrition (should be rejected)

In example 2 below, the exam committee collectively decides that all three incorrect options should be rejected by an entry-level candidate, leaving only the correct option to "guess" at, with a chance value of 100%. This item would carry a Nedelsky value of 1.0.

Example 2.

Which of the following conditions can commonly cause Carhart's notch?

1. Otitis media (should be rejected)
2. Otosclerosis (Correct answer)
3. Noise-induced hearing loss (should be rejected)
4. Cerumen impaction (should be rejected)

Each exam question therefore has its own unique Nedelsky value which is added into the passing score. Questions that are judged to be relatively difficult, such as example 1 have low Nedelsky values and tend to lower the passing score, while relatively easy questions with high Nedelsky values such as Example 2 tend to raise the passing score. The passing score for an exam is therefore dependent on the items selected for that exam. It is unlikely that passing scores will be identical from one administration to the next.

After a question appears on the certification exam, the audiology sub-committee reviews the Nedelsky value for that question to ensure consistency with candidate performance. Therefore, the Nedelsky values are not static and there is a constant evaluation process to ensure that the passing score remains current and reflects the difficulty of the exam.

Setting a Passing Score in Speech-Language Pathology

The Angoff method is used to determine the passing score on the CASLPA clinical certification examination. The Angoff method, developed by William Angoff in 1971, uses a test-centered approach, wherein subject matter experts (members of the speech-language pathology examination committee) are asked to assign a probability to each test item. Subject matter experts are asked to imagine a pool of 100 minimally competent, borderline entry level candidates and then estimate what proportion of these individuals will answer the item correctly. The sum of the proportions assigned to all of the items in a test by a subject matter expert is a referred to as a minimum performance level. The average of the minimum performance levels across subject matter experts will become the final passing score.

After an item appears on the certification exam, the speech-language pathology examination committee reviews the Angoff value for that question to ensure consistency with candidate performance. Therefore, the Angoff values are not static and there is a constant evaluation process to ensure that the passing score remains current and reflects the difficulty of the exam.