How is design debt measured or calculated?

I think designers can probably relate to 'design debt' in the same way that developers relate to 'tech debt', and there are even examples of UX debt which is probably some combination of the cost incurred from doing research, design and develop work.

Rather than making this an overly complicated question, I just want to focus on design debt in particular, as it is probably easier to quantify compared to research debt, but less easier compared to tech debt.

Are there examples of ways in which organisations have been able to not only measure the benefit of a change in design practices, but also calculate the cost of less than ideal design changes that create design debt?