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The Ottawa Sitting Scale

Details about the Ottawa Sitting Scale

Resources: To access OSS Scale documents, including Scoresheet, Instruction Sheet, and some other material, please click on the button below to request a user name and password from the authors.



Once you have these, you may visit the OSS Resources page to access the posted resources.

To read the full research paper on this scale as published in the journal Disability and Rehabilitation (see reference below), click on this button


to access the article through the Informa Healcare website.

If the above button does not work properly, please
click on this link to take you to the article: OSS at Informa

Ottawa Sitting Scale - Abstract

Purpose: We present the new Ottawa Sitting Scale (OSS) developed to characterise sitting balance in the acute care setting with slow to recover patients. We provide intra- and inter-rater reliability measures of the OSS as well as a factor analysis of scale items.

Method: Seventy-one subjects aged 21–92 years participated in this study. Original scores were compared to scores from videotaped original sessions. Performance on the OSS was compared to performance on the Berg Balance Scale (BBS) and the Physiotherapy Functional Mobility Profile (PFMP).

Results: The intra-class correlation coefficient (ICC) obtained for intra-rater reliability was excellent at 0.99 with individual item ICCs ranging from 0.746 to 0.997. Similarly, the ICCs for inter-rater reliability were also excellent at 0.96 to 0.98 with individual item ICCs ranging from 0.723 to 0.985. In the factor analysis, two main factors accounted for 77.8% of the total item variance and could be reasonably identified as movement within base of support (BOS) and movement outside BOS. The BBS and the PFMP had floor effects for the subjects with the lowest OSS scores while there was an OSS ceiling effect corresponding to those with BBS scores of approximately 10 or more.

Conclusions: The OSS discriminates between those subjects with low levels of sitting balance. Further studies will determine responsiveness to change, and compare the OSS with other postural control measures to identify the unique application of the OSS through the stages of recovery and rehabilitation.

      Keywords: Balance, outcome assessment, rehabilitation, physiotherapy