Would you like to forecast a ‘better than expected night for the GOP’? Start saying things like ‘interest levels in the elections are broadly similar between the two parties — if Dems were going to have such a great night, why aren’t they ahead in this key metric?’ or, ‘remember the enthusiasm gap closed after the Kavanaugh hearings.’
On the other hand, if you want to make the case for the Blue Wave, you’ll probably find there’s even more data to help back you up. Start by looking to YouGov/CBS News’s final MRP model (the same approach that proved super accurate in last year’s UK general election) showing a likely 225-210 Democratic win in the House.