Entries by Nathan Thompson, PhD

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Linear on the fly testing

Linear on the fly testing (LOFT) is an approach to assessment delivery that increases test security by limiting item exposure. It tries to balance the advantages of linear testing (e.g., everyone sees the same number of items, which feels fairer) with the advantages of algorithmic exams (e.g., creating a unique test for everyone). In general, […]

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What is the Hofstee method for setting cutscores?

Have you heard about standard setting approaches such as the Hofstee method, or perhaps the Angoff, Ebel, Nedelsky, or Bookmark methods?  There are certainly various ways to set a defensible cutscore or a professional credentialing or pre-employment test.  Today, we are going to discuss the Hofstee method. Why Standard Setting? Certification organizations that care about […]

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What is the Spearman-Brown formula?

The Spearman-Brown formula, also known as the Spearman-Brown Prophecy Formula or Correction, is a method used in evaluating test reliability.  It is based on the idea that split-half reliability has better assumptions than coefficient alpha but only estimates reliability for a half-length test, so you need to implement a correction that steps it up to […]

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What artificial intelligence and machine learning tell us about item banks?

Artificial intelligence (AI) and machine learning (ML) have become buzzwords over the past few years.  As I already wrote about, they are actually old news in the field of psychometrics.   Factor analysis is a classical example of ML, and item response theory also qualifies as ML.  Computerized adaptive testing is actually an application of AI […]

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Monte carlo simulation in adaptive testing

Simulation studies are an essential step in the development of a computerized adaptive test (CAT) that is defensible and meets the needs of your organization or other stakeholders. There are three types of simulations: monte carlo, real data (post hoc), and hybrid. Monte Carlo simulation is the most general-purpose approach, and the one most often […]

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What is decision consistency?

If you are involved with certification testing and are accredited by the National Commission of Certifying Agencies (NCCA), you have come across the term decision consistency.  NCCA requires you to submit a report of 11 important statistics each year, each for all active test forms.  These 11 provide a high level summary of the psychometric […]

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What is the Sympson-Hetter Item Exposure Control?

Sympson-Hetter is a method of item exposure control within the algorithm of Computerized adaptive testing (CAT).  It prevents the algorithm from over-using the best items in the pool. CAT is a powerful paradigm for delivering tests that are smarter, faster, and fairer than the traditional linear approach.  However, CAT is not without its challenges.  One is […]

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How do I develop a test security plan?

A test security plan (TSP) is a document that lays out how an assessment organization address security of its intellectual property, to protect the validity of the exam scores.  If a test is compromised, the scores become meaningless, so security is obviously important.  The test security plan helps an organization anticipate test security issues, establish […]