Applications of Item Response Theory To Practical Testing Problems

Lord, Frederic M.

doi:10.4324/9780203056615

Cited by 1,788 publications

(2,104 citation statements)

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“…60 The adaptive test starts by administering the most informative 44 item. Patient FS estimates with associated standard errors (SE) are calculated.…”

Section: Lumbar Cat and Fs Measuresmentioning

confidence: 99%

Effect of Fear-Avoidance Beliefs of Physical Activities on a Model That Predicts Risk-Adjusted Functional Status Outcomes in Patients Treated for a Lumbar Spine Dysfunction

Hart¹,

Werneke²,

Deutscher³

et al. 2011

J Orthop Sports Phys Ther

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Functional status (FS) outcomes of patients with lumbar spine dysfunctions managed in outpatient rehabilitation clinics are affected by many variables, including patient demographic variables. 35 Before clinicians can interpret associations between treatments and outcomes in a meaningful way, FS outcomes must be statistically risk-adjusted to control the effect of variables that may or may not be related to clinical care. 8,23,33,35,52 Although statistical risk adjustment models can appear complicated, 53,54 results of these models tend to be clinically logical. For example, it is clinically logical that patients who are older or patients whose symptoms are more chronic should report less FS change compared to patients who are younger or have more acute symptoms, and, indeed, results support this inverse relationship (ie, as patients age, or symptoms become chronic, FS T T STUDY DESIGN: Retrospective analysis of a prospective, longitudinal cohort study of 30 858 patients being treated for a lumbar spine dysfunction in outpatient physical therapy. T T OBJECTIVES:To determine effect of adding a single-item screening variable classifying patients with elevated versus not-elevated scores of fearavoidance beliefs of physical activities at intake, on a model predicting risk-adjusted functional status (FS) outcomes. T T BACKGROUND:Outcomes must be risk-adjusted before making meaningful interpretations. Elevated fear-avoidance beliefs scores have been predictive of poor outcomes. But the importance of elevated fear-avoidance scores in a multivariable model predicting FS outcomes needs further study. T T METHODS:Using retrospective analyses, predictive ability (R 2 ) of multivariable linear regression models of discharge FS with and without classification by elevated versus not-elevated fearavoidance scores were compared, while controlling for intake FS, age, symptom acuity, surgical history, gender, number of comorbidities, and payer. Percent variance controlled and beta coefficients (95% confidence intervals) of each variable in both models were compared. A split-half design was used for model cross-validation. Predictive ratios (predicted FS, divided by actual discharge FS) were assessed. T T RESULTS:Adding fear-avoidance beliefs classification to the discharge FS model improved (P<.001) model predictive ability but only slightly (R 2 without, and with, fear-avoidance classification, 0.2997 and 0.3010, respectively). Variables impacted models similarly (95% confidence intervals not different). Fear-avoidance classification added 0.2% data variance control to the existing model. Cross-validation was supported. Predictive ratios were 1.09 and 1.10, without and with fearavoidance, respectively. T T CONCLUSION:Although screening for elevated fear-avoidance beliefs of physical activities significantly improves the FS outcomes predictive model, the amount of additional meaningful interpretation of FS outcomes was minimal. Exploration of other clinically relevant variables designed to improve outcomes prediction is warranted...

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“…60 The adaptive test starts by administering the most informative 44 item. Patient FS estimates with associated standard errors (SE) are calculated.…”

Section: Lumbar Cat and Fs Measuresmentioning

confidence: 99%

Effect of Fear-Avoidance Beliefs of Physical Activities on a Model That Predicts Risk-Adjusted Functional Status Outcomes in Patients Treated for a Lumbar Spine Dysfunction

Hart¹,

Werneke²,

Deutscher³

et al. 2011

J Orthop Sports Phys Ther

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“…To estimate the true score, a set of items is administered to a person, and based on the item responses, the observed score is computed. This observed score is not equal to the true score because of the error of measurement [27]. For the ideal instrument, this error should be as small as possible.…”

Section: Psychometric Testing: Classical Test Theorymentioning

confidence: 94%

“…Similar to the normative values for effect sizes and responsiveness coefficients, these cutoffs should be applied with care. For example, Cronbach's alpha can be inflated by the presence of a large number of items in a scale [27]. Test-retest reliability is a correlation between two observed scores obtained from the administration of the instrument at two different times.…”

Section: Psychometric Testing: Classical Test Theorymentioning

confidence: 99%

“…The second parameter is the item discrimination parameter. In oneparameter models, like the Rasch model, it is assumed that each item is equally discriminating, that is that all item discrimination parameters are equal [27]. For this to be true, each item must contribute equally to the separation of respondents who have a high value of the underlying trait in a particular range (around the item location) from those who have a low value.…”

Section: Item Response Theory and Differential Item Functioningmentioning

confidence: 99%

“…Previous studies have shown that patients' responses to items may in fact vary as a function of the method of administration of the same instrument, creating ''mode effects'' [17,27]. The rise in computer and Internet use makes web-based assessment an inexpensive and accessible mode of administration of instruments.…”

Section: Differential Item Functioning From Different Modes Of Adminimentioning

confidence: 99%

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Statistical Considerations in the Psychometric Validation of Outcome Measures

Sikorskii

Noble

2013

Clinical Orthopaedics &Amp; Related Research

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Background The evaluation of the outcomes of total knee arthroplasty requires measurement tools that are valid, reliable, and responsive to change. However, the accuracy of any outcome measurement is determined by the validity and reliability of the instrument used. To ensure this accuracy, it is imperative that each instrument used in orthopaedics is free of biases leading to inaccurate estimates of treatment effects. Where are we now? Many patient-derived outcome instruments have been developed and tested through the application of the standard assessments that form the basis of classical test theory: validity, reliability, and responsiveness. These assessments determine if the instrument reliably measures what it is intended to measure, and if it captures differences among groups of patients or changes over time.

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