Item Response Theory (IRT) and Differential Item Functioning (DIF)

Expertise in scale development using psychometric analyses (specifically confirmatory and exploratory factor analyses), item response theory, and differential item functioning. Examples of publications include those listed below:

Dr. Amtmann led the development of item banks and short forms for the PROMIS network: Pain Interference, Pain Behavior, Fatigue Short Form for Multiple Sclerosis, and Physical Function Scale for Samples that Use Mobility Aids

Pain Interference:  Amtmann D, Cook KF, Jensen MP, Chen WH, Choi S, Revicki D, Cella D, Rothrock N, Keefe F, Callahan L, Lai JS. Development of a PROMIS item bank to measure pain interference. Pain. 2010 Jul;150(1):173-82.

Pain Behavior:  Revicki DA, Chen WH, Harnam N, Cook KF, Amtmann D, Callahan LF, Jensen MP, Keefe FJ. Development and psychometric analysis of the PROMIS pain behavior item bank. Pain. 2009 Nov;146(1-2):158-69.

Cook KF, Keefe F, Jensen MP, Roddey TS, Callahan LF, Revicki D, Bamer AM, Kim J, Chung H, Salem R, Amtmann D. Development and validation of a new self-report measure of pain behaviors. Pain. 2013 Dec;154(12):2867-76.

Fatigue:  Cook KF, Bamer AM, Roddey TS, Kraft GH, Kim J, Amtmann D. A PROMIS fatigue short form for use by individuals who have multiple sclerosis. Qual Life Res. 2012 Aug;21(6):1021-30.

Physical Function:  PROMIS Bank v1.0 – Physical Function for Samples with Mobility Aid Users


We have also developed various other item banks using IRT:

University of Washington Pain Appraisal Scale

University of Washington Pain Related Self-Efficacy Scale

University of Washington Caregiver Stress Scale

University of Washington Caregiver Benefit Scale

University of Washington Resilience Scale

University of Washington Self-Efficacy Scale (a/k/a DMSES)

Prosthetic Limb Users Survey of Mobility (PLUS-M™)


The PROMIS Statistical Analysis Plan documents the procedures we use for measure development

Reeve BB, Hays RD, Bjorner JB, Cook KF, Crane PK, Teresi JA, Thissen D, Revicki DA, Weiss DJ, Hambleton RK, Liu H, Gershon R, Reise SP, Lai JS, Cella D; PROMIS Cooperative Group. Psychometric evaluation and calibration of health-related quality of life item banks: plans for the Patient-Reported Outcomes Measurement Information System (PROMIS). Med Care. 2007 May;45(5 Suppl 1):S22-31.


IRT and other psychometric analyses can be used to evaluate the functioning of different scales in multiple sclerosis, burn, and other patient populations

Multiple Sclerosis: Amtmann D, Bamer AM, Noonan V, Lang N, Kim J, Cook KF. Comparison of the psychometric properties of two fatigue scales in multiple sclerosis. Rehabil Psychol. 2012 May;57(2):159-66.

Burn: Amtmann D, McMullen K, Kim J, Bocell FD, Chung H, Bamer A, Carrougher GJ, Gerrard P, Schneider JC, Holavanahalli RK. Psychometric Properties of the Modified 5-D Itch Scale in a Burn Model System Sample of People With Burn Injury. J Burn Care Res. 2017 Jan/Feb;38(1):e402-e408.

Other: Amtmann D, Bocell FD, Bamer A, Heinemann AW, Hoffman JM, Juengst SB, Rosenberg M, Schneider JC, Wiechman S, McMullen K. Psychometric Properties of the Satisfaction With Life Scale in People With Traumatic Brain, Spinal Cord, or Burn Injury: A National Institute on Disability, Independent Living, and Rehabilitation Research Model System Study. Assessment. 2017 Feb 1:1073191117693921.