Psychometric evaluations

Studies of reliability and validity of measurements and measurement methods

The validity of the conclusions we draw from scores of our measurements and measurement methods is entirely dependent on the quality of these. If the reliability of our assessments is impaired, or that incorrect or dubious conclusions are drawn, evaluations of treatment effect, alliance, user satisfaction, diagnostics, as well as individual clinical profiles are at stake.

Besides having its main focus on the understanding and treatment of personality disorders, the Norwegian Network of Personality Disorders dedicates a lot of resources on evaluating the psychometric properties of its clinical measures and assessment methods. Thematically, this work can be categorized topics such as; Assessment of personality disorder; Dimensionality of the DSM PD criteria; Assessment of global functioning; Dimensionality and scale reliability; Scale development; Predictive properties; and Generalizability studies.

Although all publications from our research group are chronologically listed together, we have selected the most central psychometric studies here. In addition, there are two other projects with the main focus on validity and reliability: The SIPP- and the Nor-AMP projects.

Psychometric studies

Assessment of personality disorder

  • Selvik S, Romild U, Hummelen B, Langbehn DR & Pedersen G (2018). The Iowa Personality Disorder Screen: A Validation Study In a psychiatric population that receives long-term group psychotherapy for personality related problems. Personality and Mental Health, 12: 229–240. DOI: 10.1002/pmh.1418.
  • Pedersen G, Karterud S, Hummelen B & Wilberg T (2013). The impact of extended longitudinal observation on the assessment of personality disorders. Personality and Mental Health, 7, 277–287. DOI 10.1002/pmh.1234
  • Wilberg T, Dammen T, Friis S (2000). A Comparison of the Personality Diagnostic Questionnaire -4+ (PDQ-4) with LEAD Standard Diagnoses in Highly Symptomatic Patients. Comprehensive Psychiatry, 41(4), 295-302.

Dimensionality of the DSM PD criteria

  • Paap MCS, Heltne A, Pedersen G, Selvik SG, Frans N, Wilberg T & Hummelen B (2021). More is more: evidence for the incremental value of the SCID-II/SCID-5-PD specific factors over and above a general PD factor. Personality Disorders: Theory, Research, and Treatment.
  • Hummelen, B., Pedersen, G., Wilberg, T., Karterud, S. (2015). Poor Validity of the DSM-IV Schizoid Personality Disorder Construct as a Diagnostic Category. Journal of Personality Disorders, 28, 1-13. doi: 10.1521/pedi_2014_28_159.
  • Hummelen B, Pedersen G & Karterud S (2012). Some suggestions for the DSM-5 schizotypal personality disorder construct. Comprehensive Psychiatry, 53(4), 341-349.
  • Falkum E, Pedersen G & Karterud S (2009). Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, paranoid personality disorder diagnosis: a unitary or a two-dimensional construct? Comprehansive Psychiatry, 50(6), 533-541.
  • Paap MCS, Bræken J, Pedersen G, Urnes Ø, Karterud S, Wilberg T, & Hummelen B (2017). A Psychometric Evaluation of the DSM-IV Criteria for Antisocial Personality Disorder: Dimensionality, Local Reliability, and Differential Item Functioning Across Gender. Assessment, 1-13.
  • Johansen M, Karterud S, Pedersen G, Gude T & Falkum E (2004). An investigation of the prototype validity of the borderline DSM-IV criteria. Acta Psyciatrica Scandinavica, 109(4), 289-298.
  • Karterud S, Øyen M & Pedersen G (2011). Validity aspects of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, narcissistic personality disorder construct. Comprehensive Psychiatry, 52(5), 517–526.
  • Bakkevig JF & Karterud S (2010). Is the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, histrionic personality disorder category a valid construct? Comprehensive Psychiatry, 51(5), 462-70.
  • Hummelen B, Wilberg T, Pedersen G, Karterud S. (2006). An investigation of the validity of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition avoidant personality disorder construct as a prototype category and the psychometric properties of the diagnostic criteria. Comprehensive Psychiatry, 47(5):376-83.
  • Hummelen B, Wilberg T, Pedersen G & Karterud S (2008). The Quality of the DSM-IV Obsessive-Compulsive Personality Disorder Construct as a Prototype Category. Journal of Nervous & Mental Disease, 196(6), 446-455.
  • Gude T, Karterud S, Pedersen G, Falkum E. (2006). The quality of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition dependent personality disorder prototype. Comprehensive Psychiatry, 47(6):456-62.
  • Wilberg T, Hummelen B, Pedersen G & Karterud S (2008). A study of patients with personality disorder not otherwise specified. Comprehensive Psychiatry, 49(5), 460-468.

Assessment of global functioning

  • Pedersen G, Urnes Ø, Hummelen B, Wilberg T & Kvarstein EH (2018). Revised manual for the Global Assessment of Functioning scale. European Psychiatry, 51, 16–19.
  • Støre-Valen J, Ryum T, Pedersen G, Pripp AH , Jose PE & Karterud S (2015). Does a Web-Based Feedback Training Program Result in Improved Reliability in Clinicians’ Ratings of the Global Assessment of Functioning (GAF) Scale? Psychological Assessment. 27(3), 865-873. doi: 10.1037/pas0000086.
  • Pedersen G & Karterud S (2012). The symptom and function dimensions of the Global Assessment of Functioning (GAF) scale. Comprehensive Psychiatry, 53(3), 292-298.
  • Pedersen G, Hagtvet KA & Karterud S. (2007). Generalizability studies of the Global assessment of functioning (GAF) - Split version. Comprehensive Psychiatry. 48, 88– 94.
  • Karterud S, Pedersen G, Løvdahl H, Friis S. (1998). Global assessment of functioning - split version. Background and scoring guidelines. Psychiatric clinic, Ullevaal university hospital, Oslo.

Dimensionality and scale reliability

  • Pedersen G, Kvarstein EH, Wilberg T, Folmo EJ, Burlingame G & Lorentzen S. (2021). The Group Questionnaire (GQ) – Psychometric properties among outpatients with personality disorders. Group Dynamics: Theory, Research, and Practice.
  • Pedersen G, Norman-Eide E, Eikenæs IU-M, Kvarstein E, Wilberg T (2021). Psychometric evaluation of the Norwegian Toronto Alexithymia Scale (TAS-20) in a multi-site clinical sample of patients with personality disorders and personality problems. Journal of Clinical Psychology. DOI: 10.1002/jclp.23270
  • Paap MCS, Meijer RR, Cohen-Kettenis PT, Richter-Appelt H, de Cuypere G, Kreukels BPC, Pedersen G, Karterud S, Malt UF & Haraldsen I (2021). Why the factorial structure of the SCL-90-R is unstable: comparing patient groups with different levels of psychological distress using Mokken Scale Analysis. Psychiatry Research, 200(2-3):819-826. DOI: 10.1016/j.psychres.2012.03.012.
  • Breivik R, Wilberg T, Evensen J, Røssberg JI, Dahl HSJ, Pedersen G (2020). Countertransference feelings and personality disorders: A psychometric evaluation of a brief version of the Feeling Word Checklist (FWC-BV). BMC Psychiatry, 20:141.
  • Pedersen G, Kvarstein EH & Wilberg T (2017). The Work and Social Adjustment Scale: Psychometric properties and validity among patients with personality disorders and traits. Personality and Mental Health.11, 215–228. DOI: 10.1002/pmh.1382
  • Pedersen G, Urnes Ø, Kvarstein EH, Karterud S. (2016). The three factors of the Psychoticism scale of SCL-90-R. Personality and Mental Health, 10, 244-255. doi: 10.1002/pmh.1278.
  • Pedersen G, Eikenæs I, Urnes Ø, Skulberg GM & Wilberg S (2015). Experiences in Close Relationships - Psychometric properties among patients with personality disorders. Personality and Mental Health, 9(3), 208-219. DOI 10.1002/pmh.1298.
  • Pedersen G, Johansen MS, Wilberg T & Karterud S (2014). Testing Different Versions of the Affective Neuroscience Personality Scales in a Clinical Sample. PLoSONE 9(10): e109394. doi:10.1371/journal.pone.0109394.
  • Paap MCS, Meijer RR, van Bebber J, Pedersen G, Karterud S, Hellem F & Haraldsen IR (2011). A study of the dimensionality and measurement precision of the SCL-90-R using Item Response Theory. International Journal of Methods in Psychiatric Research, 20(3), e39–e55.
  • Pedersen G, Karterud S (2002). Ward Atmosphere Scale for Therapeutic Programs (WAS-TP): Psychometric properties and clinical benefits. Therapeutic Communities, 23(4): 261-269.
  • Pedersen G (2002). Norsk revidert versjon av Inventory of Interpersonal Problems - Circumplex (IIP-C). Tidsskrift for Norsk Psykologforening, 39, 25-34.

Scale development

  • Pedersen G, Tybring-Petersen K, Tønder M, Arnestad TB, Møller AC & Øya T (2013). Spørreskjema for måling av kroppsopplevelse. Tidsskrift for Norsk Psykologforening, 50, 992-998.

Predictive properties

  • Pedersen G & Karterud S (2010). Using measures from the SCL-90-R to screen for personality disorders. Personality and Mental Health, 4(2), 121-132.
  • Pedersen G, Karterud S (2004). Is SCL-90R helpful for the clinician in assessing DSM-IV symptom disorders? Acta Psyciatrica Scandinavica, 110(3): 215-224.
  • Karterud S, Friis S, Irion T, Mehlum L, Vaglum P & Vaglum S (1995). A SCL-90-R derived index of the severity of personality disorders. Journal of Personality Disorders, 9, 112–123.

Generalizability studies

  • Folmo EJ, Karterud SW, Bremer K, Walther KL, Kvarstein EH & Pedersen GAF (2017). The design of the MBT-G adherence and quality scale. Scandinavian Journal of Psychology, 58, 341–349. DOI: 10.1111/sjop.12375.
  • Karterud S, Pedersen G, Engen M, Johansen MS, Johansson P, Urnes Ø, Wilberg T & Bateman A (2012). The MBT adherence and Competence Scale (MBT-ACS): Development, structure and reliability. Psychotherapy Research, 23(6), 705-717. DOI: 10.1080/10503307.2012.708795.
  • Pedersen G, Hagtvet KA & Karterud S (2011). Interpersonal problems: Self-therapist agreement and therapist consensus. Journal of Clinical Psychology, 67(3), 308-317.


Published Feb. 8, 2022 2:32 PM - Last modified Feb. 23, 2022 4:35 PM