Introduction to the Moss Attention Rating Scale

The Moss Attention Rating Scale (MARS) was developed by John Whyte, MD, PhD, Tessa Hart, PhD, and colleagues at the Moss TBI Model System at MossRehab Hospital and Moss Rehabilitation Research Institute. Collaborators from other TBI Model System centers were also instrumental in testing the reliability of the MARS.

Attention deficits are nearly ubiquitous after TBI, but can be somewhat problematic to measure for several reasons. First, “attention” is not a unitary construct but encompasses a number of cognitive processes from arousal and basic orienting to higher level processes overlapping with executive control (multi-tasking, error monitoring, etc.). Psychometric measures of some of these constructs are available, but an attention battery may not be feasible in the clinical setting, either because of time constraints or because patients are too impaired to undergo testing. Traditional attention tests are typically highly structured, time-limited, and administered in an environment that minimizes distractions. Thus, they may not adequately measure clinically important dimensions of attention such as resistance to distraction, the ability to make decisions about how to deploy one’s attention, or consistency of attention over time. One may make informal or bedside assessments of a patient’s attention in the real-world environment, but these may not be reliable, and do not allow for quantitative assessment of changes over time (or in response to treatment).

The MARS was designed as an observational rating scale to provide a reliable, quantitative and ecologically valid measure of attention-related behavior after TBI. Items were developed and refined using literature review and expert consultation, focus groups of expert TBI clinicians, and the results of two pilot studies (see Whyte et al., 2003). A 45-item research version of the MARS was subjected to item response analysis (Whyte et al., 2003) and both exploratory and confirmatory factor analysis (Hart et al., 2006) to produce the current, 22-item MARS. Each item is a behavioral descriptor rated on a 5-point Likert-type scale according to how well that behavior describes the patient, ranging from “definitely true” to “definitely false.” Items are phrased so that the rater considers behaviors indicative of both good and impaired attention. Half the items relate to the 3 correlated factors found for the MARS: Restlessness/ Distractibility, Initiation, and Sustained/ Consistent Attention (Hart et al., 2006) and may be used to compute factor scores. The total raw MARS score may be converted to an interval metric from 0-100 (see Scoring section for how to compute factor and logit scores).

Since the MARS is based on observable behavior it is not appropriate for use with patients in the minimally conscious or vegetative states; validation studies thus far have been restricted to patients at Rancho level IV or higher. Item response analysis suggested that the “difficulty level” of the MARS is most appropriate for persons with moderate to severe attention deficits (Whyte et al., 2003). It has been tested thus far in inpatient TBI rehabilitation settings.

Information regarding the MARS was contributed by the Moss TBI Model Sytem, Philadelphia. Please contact Tessa Hart, Ph.D., at for more information.

If you find the information in the COMBI useful, please mention it when citing sources of information. The information on the MARS may be cited as:

Hart, T. (2008). The Moss Attention Rating Scale. The Center for Outcome Measurement in Brain Injury. http://www.tbims.org/combi/mars ( accessed ).