title: An emotional functioning item bank of 24 items for computerized adaptive testing (CAT) was established.
abstract: OBJECTIVE
  To improve measurement precision, the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Group is developing an item bank for computerized adaptive testing (CAT) of emotional functioning (EF). The item bank will be within the conceptual framework of the widely used EORTC Quality of Life questionnaire (QLQ-C30).
  
  
  METHODS
  On the basis of literature search and evaluations by international samples of experts and cancer patients, 38 candidate items were developed. The psychometric properties of the items were evaluated in a large international sample of cancer patients. This included evaluations of dimensionality, item response theory (IRT) model fit, differential item functioning (DIF), and of measurement precision/statistical power.
  
  
  RESULTS
  Responses were obtained from 1,023 cancer patients from four countries. The evaluations showed that 24 items could be included in a unidimensional IRT model. DIF did not seem to have any significant impact on the estimation of EF. Evaluations indicated that the CAT measure may reduce sample size requirements by up to 50% compared to the QLQ-C30 EF scale without reducing power.
  
  
  CONCLUSIONS
  On the basis of thorough psychometric evaluations, we have established an EF item bank of 24 items. This will allow for more precise and flexible measurement of EF, while maintaining backward compatibility with the QLQ-C30 EF scale.
authors.affiliation: The Research Unit, Department of Palliative Medicine, Bispebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, 2400 Copenhagen, Denmark. Electronic address: Morten.Aagaard.Petersen@regionh.dk.
authors.forename: Morten Aa
authors.initials: MA
authors.lastname: Petersen
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Medical University of Innsbruck, Christoph-Probst-Platz 1, Innrain 52, A - 6020 Innsbruck, Austria.
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Gamper
authors.affiliation: Psycho-oncology Unit, Sant'Andrea Hospital, Department of Oncological Sciences, Faculty of Medicine and Psychology, Sapienza University, Via di Grottarossa 1035 - 00189 Rome, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Costantini
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Medical University of Innsbruck, Christoph-Probst-Platz 1, Innrain 52, A - 6020 Innsbruck, Austria.
authors.forename: Johannes M
authors.initials: JM
authors.lastname: Giesinger
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Medical University of Innsbruck, Christoph-Probst-Platz 1, Innrain 52, A - 6020 Innsbruck, Austria.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Holzner
authors.affiliation: Surgical Unit, University of Southampton, University Road, Highfield, Southampton SO17 1BJ, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Johnson
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Medical University of Innsbruck, Christoph-Probst-Platz 1, Innrain 52, A - 6020 Innsbruck, Austria.
authors.forename: Monika
authors.initials: M
authors.lastname: Sztankay
authors.affiliation: Lynda Jackson Macmillan Centre, Mount Vernon Cancer Centre, Northwood, Middlesex HA6 2RN, UK.
authors.forename: Teresa
authors.initials: T
authors.lastname: Young
authors.affiliation: The Research Unit, Department of Palliative Medicine, Bispebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, 2400 Copenhagen, Denmark; Institute of Public Health, University of Copenhagen, Øster Farimagsgade 5, P.O. Box 2099, 1014 Copenhagen, Denmark.
authors.forename: Mogens
authors.initials: M
authors.lastname: Groenvold
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004644:Emotions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000503:physiopathology* / Q000523:psychology*; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life; D011795:Surveys and Questionnaires
keywords: Computerized adaptive testing; EORTC QLQ-C30; Emotional functioning; Item response theory; Oncology; Patient-reported outcome