Ratios are used sequentially or not.
Profit margins are also expressed in %.
However there is no compounding @ work.
% Growth doesn't have to be "compoundable".
In addition, as rightly said, it's not always doable.
What's good with Ratios is their dimensionless property.
It allows you to compare Apple and Orange. Compound or not.
Ratios, if not compoundable, or more generally, expressed as parts of the whole, are not comparable or even meaningful across events.
You CAN say, there was a certain % growth between year 2000 and 2010. However, that may add dependencies and constraints that was not present in a more general description, ie. a
one time event, non-repeatable. Such descriptions and graphs can easily be used to mislead due to ambiguity.
For ratios to truly work, they must be universal, and not constrained by undercommunicated expectations. So should be compoundable and/or describe level of completedness, up to certain realistic points.
This is not about correct expression, but about correct understanding, so as long as understanding is right, all is right.
Ie. a system generating +0.0001% may fail when volume*price exceeds a certain value in practical trading, as things tend to break when they scale to reality, but the maths underneath should be sound and non-ambiguous.
However, my understanding may not be generally acceptable to general trader knowledge, and if so, I will rest my case
I like and respect ratios so much as to stand up for them a little bit
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