Defining a physical disability seems like it should be straightforward. Something doesn’t work the way it should! Should is, of course, a very subjective term; everyone would have a different definition “should” in this context.
What is Normal?
It might be easier to say there’s a norm, and most of us deviate to some degree or another from that norm. Within certain amounts, we can perform most or all the tasks associated with a certain occupation or activity, but deviating further gives us less likelihood of being successful.
For example, if have full (or essentially full) use of both arms and hands, then most things in life that require the use of hands will be something you’re potentially able to do.
Drive a vehicle
Type a document
Operate an industrial machine
This doesn’t mean that you can’t do some or all of these things without hands, or even arms! It just means that the activity itself was likely designed first for someone who has little to no impairments. Fortunately, more and more activities at work and leisure are being designed to be more accessible every day, but there’s still a huge barrier that exists for anyone who has physical challenges.
That barrier has a huge impact on employability, employment, as well as the earnings potential over time.
Physical Disabilities on Un-employment & Under-Employment
On average a person with a physical disability, and able to seek work, is at least twice as likely to be unemployed vs a peer with the same education level and background experience. Of those that are employed, they will often earn significantly less income than their peers, and are more than twice as likely to be under-employed and unable to earn a living wage.
These are probably surprising statistics. And they shift the focus of the conversation to some degree as well. Perhaps you were at one time able to do activities that you can’t do now because of a physical barrier. Maybe you lost the use of limbs, loss coordination, can’t walk, stand, or sit for more than 5-10 minutes at a time? Or, you might not be able to get where you used to be able to, or need to be able to for work now.
Physical Disabilities and Functional Employment
The issue is not if you can do something once. It’s very possible that even with a physical disability you can perform a task a single time, or for short periods of time. But you likely need support to do so or a great deal of effort.
You have a barrier. And that barrier is that you can’t perform activities or work now without significant assistance, and you can’t do it everyday, all-day, every week, all year, for the next couple decades.
This is, essentially, the basic idea behind the idea of evaluating Substantially Gainful Activity (SGA). SGA is one of the cornerstone requirements for SSI & SSDI benefits for physical disabilities. In this link, we discuss SGA further, with examples to demonstrate how physical and mental health disabilities factor into benefits scenarios.