Is there objective data on whether, in general, that more authoritarian countries have more ambiguous laws on the books?

It is said by some Western sources that China has exceedingly vague laws on the book, which allow the executive branch to make up violations against the political undesirables du jour. (This is even claimed so by a US Embassy, which also includes Iran in that category.)

I'm curious if there are any political science studies that try to objectively (to the extent that's possible) generalize such findings. Do authoritarian countries in general have more vague laws on the books?