I think this is what they were saying--pre-tax refers to traditional, post-tax to roth. Only traditional ira/401k reduces the marginal tax rate. So the decision

I think this is what they were saying--pre-tax refers to traditional, post-tax to roth. Only traditional ira/401k reduces the marginal tax rate. So the decision to go for traditional or roth depends on how you expect your tax bracket to change.