What Is the CAT and How Does it Work?

NCLEX - A computer adaptive test

Taking the NCLEX ® is a testing experience much different than what most students are used to. Both the NCLEX-RN ® and NCLEX-PN® are CAT exams and must be approached differently.

Why do cats purr? What is a group of cats called? Why do cats hate water? What vaccinations do kittens need and when?

Those are all questions you won’t need to prepare for — this is a different kind of CAT test. (Sorry, I couldn’t help it. I’ll show myself out.)

The NCLEX is a computer adaptive test (CAT). If you’re preparing for an upcoming NCLEX exam, here is some information about computer adaptive testing . . . 

When did the NCLEX begin using computer adaptive testing?

April 1, 1994. Before that date, the NCLEX was your typical paper-and-pencil exam and was only administered twice a year due to the logistics of administration (i.e. ordering testing materials, hiring proctors, shipping test booklets to be graded, etc.)

What is the difference between a computer adaptive test and a paper-and-pencil test?

The obvious difference is one is taken on a computer and the other isn’t. (Care to take a guess which one is the computer exam?)

On a conventional paper-and-pencil exam, questions are predetermined and standard. Computer adaptive testing asks test-takers different questions based upon their previous responses.

How Does CAT work?

Computer adaptive testing works by measuring your competency with each question asked.

If you answer a question correctly, the computer re-estimates your ability and presents a new question that is a little more difficult — a question that you should have a 50% chance of answering correctly.

Conversely, if you answer a question incorrectly, the computer will present a new question that is slightly less difficult.

This pattern continues until you run out of time or until the computer identifies your competency level as above or below the passing standard.

How Does the Computer Determine Passing or Failing?

Whether you pass or fail the NCLEX is determined by one of the following three rules:

1. 95% Confidence Interval Rule

The 95% Confidence Interval Rule is most common among test takers. With this rule, the computer will stop presenting questions when it is 95% certain that the test taker is either clearly above or clearly below the passing standard for competency.

2. Maximum-Length Rule

Sometimes a test taker demonstrates ability that is very close to the “95% confidence interval” but not quite there. In this case, the computer will continue to present questions until that mark is established or until the maximum number of items is reached. (Hence, the “Maximum-Length Rule.”) Once the test taker has completed the maximum number of items, the computer determines whether you pass or fail with a final ability estimate.

3. R.O.O.T. Rule (Run-out-of-time)

If a test taker runs out of time before completing the minimum number of items it results in a failed exam. If the test taker runs out of time and has completed the minimum number of items, the computer determines pass or fail with a final ability estimate.

How much time and how many items?

For both the NCLEX-RN and the NCLEX-PN the maximum amount of time is five hours, the minimum number of items is 75, and the maximum number of items is 145.

If you’re a nursing student preparing to take the NCLEX® exam, UWorld is the gold standard for NCLEX prep. We can help guide your success from classroom to clinical with thousands of questions that mimic the exam, detailed rationales, vivid illustrations, and precise performance tracking. Discover why over 700,000 nursing students have trusted us for their exam prep since 2015.

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