the only test of polls, or any other predictive attempt, is how it matches the actual outcome.
The people on FR who are excoriating the ‘MSM’ polls would be praising them to the stars if they showed Trump winning handily. Not that most polls aren’t BS, but they aren’t actual attempts at prediction so much as psy-ops.
With polls, it’s not the number of the responses as much as the QUALITY of the responses- any response without demographical data for age, income, sex, religion and race correlated is just some random person on the internet clicking a box.
So, the polls keep getting 'fixed' to make sure Trump doesn't pull ahead.