Psychometric Properties of the General Movement Optimality Score using Rasch Measurement

Vanessa Maziero Barbosa*, Everett V Smith, Arend Bos, Giovanni Cioni, Fabrizio Ferrari, Andrea Guzzetta, Peter B Marschik, Jasmin Pansy, Berndt Urlesberger, Hong Yang, Christa Einspieler

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


AIM: To explore the psychometric properties of the general movements optimality score (GMOS) by examining its dimensionality, rating scale functioning, and item hierarchies using Rasch measurement.

METHODS: Secondary data analysis of the GMOS data for video-recording of 383 infants with uni-, multidimensional, and mixed Rasch partial credit models. Videos were scored based on the global General Movement Assessment categories, and on the amplitude, speed, spatial range, proximal and distal rotations, onset and offset, tremulous and cramped components of the upper and lower extremities (21 items), resulting in the GMOS.

RESULTS: The GMOS data fits best to a unidimensional mixed Rasch model with three different classes of infants, with all but two items contributing to the infants' separation. Rating scales functioned well for 19 items. Item difficulty hierarchies varied depending on infants' class. No floor effect and no substantive gaps between item difficulty estimates were found.

CONCLUSION: The GMOS has strong psychometric properties to distinguish infants with different functional motor performance and provides a quantitative measure of quality of movement.

INTERPRETATION: The GMOS can be confidently used to assist with early diagnosis, grade motor performance, and provide a solid base to study individual general movement developmental trajectories.

Original languageEnglish
Pages (from-to)17-37
Number of pages21
JournalJournal of Applied Measurement
Issue number1
Publication statusPublished - 1-Jan-2020


  • Humans
  • Infant
  • Logistic Models
  • Movement
  • Psychometrics
  • Records
  • Reproducibility of Results
  • Surveys and Questionnaires

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