Do you have a source for that claim? Genuine question.

My intuition is that the types of impact are widely different, so hard to reduce to a single number that can be compared.

Wait, from the perspective of a Third Worldist, isn’t Perry Anderson’s Western Marxism precisely the problem? That’s at least what I gathered, without having read Losurdo specifically, from reviews of his work such as this one https://monthlyreview.org/press/201187/