This makes no sense. A spectrum would involve everyone having the same problem to different degrees; anything that addressed that problem would consistently show an effect.
I learned the opposite, that the term spectrum is used when it is not same problem to different degrees. That's how the autism spectrum was explained to me, because the problem differs over the spectrum. In opposition to "level" or "gradient", which is intended to be something more linear over the same dimension.
I believe this redefinition of the term comes from how a "rainbow spectrum" is perceived, as different colors (and not as it is defined, as a linear degree of wavelength)
The autism spectrum, in specific, was unified from what had been listed as separate disorders. That was done because the view was reached that these disorders reflected different degrees of the same underlying problem.
No, precisely the opposite. They weren't different degrees of the same underlying problem, they were a few different combinations of symptoms from a few different symptom categories: social, communication, and repetitive behaviors.
Something being a spectrum is not just a matter of intensity on a single axis ("more or less autistic"). Imagine a graph of the visible light spectrum, wavelengths map to symptoms and their intensities map to symptom severities.
ASD is a spectrum because different individuals have different levels of impairment in each area.
Consider this: Why is ASD a spectrum disorder and social anxiety isn't? Surely you don't believe that anxiety only comes in a single level of severity.
That’s difficult to measure objectively. Many schools lack the specialists who can spot this, and when they do, Teachers try different adaptations that help kids, so you’re going to have varying results based on the adaptations the person understands.
I have something called APD (auditory processing disorder) which essentially means that the areas of my brain that listen to speech, especially higher pitched female speech aren’t fully developed — I had chronic ear infections and my heading was negatively impacted. I adapted well, although with undiagnosed ADHD. Others do not for a variety of reasons.
There is a fashion for calling everything a spectrum. Maybe "range" would be a better term for a linear progression.
So something may help type 1 dyslexia, but not help type 2 or type 3 etc.
The say that spectrum is inaccurate and the fruit salad is a better name) analogy/description.
Like with fruit salad, you can serve it to a table of people and everyone will have fruit salad on their plate, but it will be randomly varied for all. Some will have a lot of one fruit and a few others. Some will have all but one and so on.