I wouldn't agree with the conclusion of being truly inferior - there could be ongoing issues with the work context. I'll put it another way: Graham says we can

I wouldn't agree with the conclusion of being truly inferior - there could be ongoing issues with the work context. I'll put it another way: Graham says we can look at just the performance by group to detect bias in selection. But there could be bias in selection, and A) different treatment after selection, which would not be revealed through Graham's test. Or could also be bias in selection and B) continuous reminders of stereotypes triggering stereotype threat, and this would also not be revealed. Now you could point to a tech company with few underrepresented minorities, let's say 1%. If there's no overt bias in the work environment then people should succeed and if they don't they're just worse performers. On the other hand, if you're in the 1%, just noticing the underrepresentation among your coworkers might be a constant reminder of stereotypes. I don't claim to have a simple solution for this.