The WOSI score: why “higher” can mean better or worse

The 21 items fall into four domains: physical symptoms (items 1 to 10), sports, recreation and work (items 11 to 14), lifestyle (items 15 to 18) and emotions (items 19 to 21). Each item is marked on a 100 mm line from no symptom to the extreme, so a domain’s maximum is 100 times its number of items: 1000 for physical symptoms, 400 each for sports and lifestyle, and 300 for emotions.

The raw total adds the 21 items, so it runs from 0 to 2100 and 0 is the best possible result. An 11-point numerical version is also used, in which case the raw total runs from 0 to 210.

Many publications convert the raw total to a percentage of normal as (maximum − raw score) divided by the maximum, times 100. Then 100% is a shoulder with no impairment and a higher number is better. The calculator on this site reports that percentage, shows the raw total alongside it, and says which is which.

Check the scale before the number. A WOSI of 450 in one paper and 79% in another can describe the same shoulder: 450 out of 2100 is about 21% of the maximum impairment, or 79% of normal. Comparing a raw total with a percentage, or a raw total from a 0 to 10 version with one from a 0 to 100 version, gives nonsense.

No minimal clinically important difference is shown on the calculator page, because we could not verify a published value; use one from a population and follow-up interval that match your own.

The WOSI is the disease-specific measure for shoulder instability and covers fear, protection of the arm and the effect on sport, which a general shoulder score does not. For the single question of recurrence and motion, the Rowe score weights those directly; for general shoulder function, use the SPADI or ASES.