The chances of the House of Representatives switching hands to Democratic control are best described as slim to none, with very little slim involved. Additionally, since this is a midterm election year, there isn't anything to look at concerning the President -- statistically speaking. That leaves us with the Senate to play with, and boy what fun we can have with the Senate.
The Democrats currently control the Senate, but there is a fairly good chance that it will switch hands after the midterm elections. This is the kind of year that the terms 'nail bitter' and 'cliff hanger' were made for. The most optimistic statistics that I can find give the Republicans a 30% chance of taking control of the Senate, while the vast majority of statisticians put the Republican's chance of Senate control after the midterms at 50% or greater.
It all comes down to the decisions of a few people in a few states that might be willing to switch their vote from one candidate to another. There haven't been margins this close (that I am aware of) since Gore vs Bush in the Florida elections of 2000.
So, where do we stand?
I have been limiting the statistics and polls that I have been watching. There is a little danger to this in the sense that something could happen in a state that I'm not paying attention to that would cause the probability of overall control of the Senate to switch without my knowledge. That being said, I am currently expect control of the Senate to rest on three states:
Iowa, Alaska, and Colorado.
Despite the most recent poll, my statistics still put Colorado into Democratic hands. Polling data also places Alaska into Democratic hands, but there are so few polls that my confidence isn't very high concerning Alaska.
But the state that is the most interesting is Iowa. Iowa is a scatter-shot pattern of polls all over the place. Even looking at the statistical median, that will help eliminate outliers, Iowa is a coin flip.
So how do all these different states fit into the overall picture of Senate control? As my statistics break down right now, the Republicans should have 50 seats. The Democrats, and the Independents that caucus with them, should have 50 seats (assuming that Greg Orman caucuses with the Democrats). That will keep the Senate control in Democratic hands since Joe Biden, being the Vice President, is the President of the Senate.
If the coin toss of Iowa goes the other way, then that will give the Democrats and Independents a 51-49 majority in the Senate. So despite the close race in Iowa, I give the Democrats good odds of retaining control of the Senate.