Examining the psychometric properties of a sport-related concussion survey: a Rasch measurement approach

Abstract

Background: Awareness of sport-related concussion (SRC) is an essential step in increasing the number of athletes or parents who report on SRC. This awareness is important, as there is no established data on medical care at youth-level sports and may be limited to individuals with only first aid training. In this circumstance, aside from the coach, it is the players and their parents who need to be aware of possible signs and symptoms. The aim of this study was to examine the psychometric properties of a parent and player concussion survey intended for use before and after an education campaign regarding SRC.

Methods: 1441 questionnaires were received from parents and 284 questionnaires from players. The responses to the sixteen-item section of the questionnaire's 'recognition of signs and symptoms' were submitted to psychometric analysis using the dichotomous and polytomous Rasch model via the Rasch Unidimensional Measurement Model software RUMM2030. The Rasch model of Modern Test Theory can be considered a refinement of, or advance on, traditional analyses of an instrument's psychometric properties.

Results: The main finding is that these sixteen items measure two factors: items that are symptoms of concussion and items that are not symptoms of concussion. Parents and athletes were able to identify most or all of the symptoms, but were not as good at distinguishing symptoms that are not symptoms of concussion. Analyzing these responses revealed differential item functioning for parents and athletes on non-symptom items. When the DIF was resolved a significant difference was found between parents and athletes.

Conclusions: The main finding is that the items measure two 'dimensions' in concussion symptom recognition. The first dimension consists of those items that are symptoms of concussion and the second dimension of those items that are not symptoms of concussion. Parents and players were able to identify most or all of the symptoms of concussion, so one would not expect to pick up any positive change on these items after an education campaign. Parents and players were not as good at distinguishing symptoms that are not symptoms of concussion. It is on these items that one may possibly expect improvement to manifest, so to evaluate the effectiveness of an education campaign it would pay to look for improvement in distinguishing symptoms that are not symptoms of concussion.

Keywords: Concussion awareness; Education; Measurement; Rasch model.

Fig. 1

Histogram of person locations (left) and labeled items (right) on the same measurement continuum. Item labels in blue are the items that are not symptoms of concussion, and labels in red are of items that are symptoms of concussion

Fig. 2

DIF for item 11 Sharp neck pain: For the same overall level of awareness of concussion symptoms, athletes identified this item correctly as not a symptom of concussion more than parents did

Fig. 3

Person distribution from the analysis of items that are symptoms of concussion (top) and person distribution from the analysis of items that are not symptoms of concussion (bottom)