What role did Comey and the Podesta email leaks play in Clinton's loss?

Question

Claims that Hillary Clinton's election loss was a consequence of:

1. Russian involvement in the acquisition and subsequent leaking of emails from the DNC and Clinton campaign chair John Podesta.

2. FBI director James Comey's claim in a letter to Congress that new emails relevant to the investigation of Clinton's email servers have been discovered.

have been made by many prominent Hillary supporters as well various columns and op-eds in reputable newspapers. Indeed, Hillary herself has, in stark terms, asserted that the alleged Russian cyber attack was an "attack against [the United States]". She has explicitly blamed Comey for her loss as well.

Is there any reliable data to suggest that these two factors significantly, or perhaps even decisively, resulted in Hillary Clinton's loss? Did these two issues 'swing' undecided voters in swing states to Trump?

It should go without saying that I'm interested in an objective answer based on reputable sources, not partisanship or polemics.

Note that this question is similar; however, given that it does not discuss Comey and that the single answer lacks concrete data and is rather polemical, I have chosen to post a new question.

Answer 1

As best I can tell, no one has researched the question of whether the Comey letters impacted the election. To be effective, that should have been done the day of the election or soon after. Now it would be polluted by things people may have learned since the election.

Such examination is also flawed in the sense that people don't necessarily know why they voted the way that they did. So asking can be ineffective. It's often better to study reactions to related questions. For example, if people don't know that James Comey is the director of the FBI, they are unlikely to be affected by his communications. But as far as I know, no one did that kind of research either.

There is some historical data. We can see, for example, how the Real Clear Politics polling average moved around that time. The letters were sent October 28th and November 6th, 2016. Clinton's lead was the highest at 7.1% on October 17th and 18th. It had dropped to 3.9% by October 28th and to 2.2% on November 6th. The final result is currently shown as 48.1% to 46% or a 2.1% lead.

So if the the second letter had any effect whatsoever, it was countered by other effects. The final result of the election was indistinguishable from the average shown on November 6th.

The first letter could have had a net effect; the polling does not refute it. However, the change was larger before (-3.2%) the letter was released than after (-1.8%). I.e. it is equally possible that the first letter had no effect and other initiatives were responsible.

As such, if a candidate claims that she lost because of the Comey letter, she is doing so without any objective evidence. She is only engaging in polemics.

Answer 2

There is no measured empirical evidence that these two events had any outcome on the election, one way or the other. For example no data exists to date that states: group of x voters changed their vote or emerged as new voters for Trump in WI, MI, or PA, or likewise against Hillary Clinton due to either of your claims. You can track correlation, but frankly the polls were so off I don't know what that would solve. Correlation would also include everything else that occurred simultaneously and would not isolate your events. Sorry, but you can't source what doesn't exist.

We don't know how much of an effect the revelations had or if they had an effect at all, or if it produced a counter-intuitive effect, like rallying Clinton's base.