https://www.americanthinker.com/articles/2018/11/the_breaking_factors_that_will_determine_the_election.html
As I have done every two years for quite some time, here are my predictions for the midterms.
House of Representatives
There are several dozen House races and five Senate races where one candidate or the other has a lead of 2 points or less in the most recent survey. Picking individual winners in these House races is hazardous since there are few public polls of these districts . Another few dozen House seats show a candidate leading by five points or less. The great majority of the close House races are Republican-held seats, hence their vulnerability to Democrats taking over the House, where a net pickup of 23 seats is required.
Most every analyst — Larry Sabato, Stuart Rothenberg, the Cook Political Report, the Real Clear Politics average, Nate Silver’s fivethirtyeight.com, Nate Cohn in the upshot in the New York Times — is predicting a pickup for the Democrats of more than the 23 seats needed. Several have increased their range of the likely pickup in the last week to the 30 to 40 seat range.
Polling is becoming more difficult with ever lower response rates to telephone surveys with live callers. . There are sometimes higher response rates to automated surveys, whether by phone or online (though not much higher), and there are issues related to whether such surveys reach a representative sample of likely voters.
Rasmussen, an automated survey, shows Trump with a positive approval score, and most other surveys show him 8-12 or more points net negative. The generic ballot for which party voters prefer control Congress has consistently shown large margins for the Democrats, currently over 7 points on average, though a few surveys have shown smaller margins this week.
The Democrats seem poised for significant gains in the House delegation in Pennsylvania , due to court-ordered redistricting. Democrats should also net big gains in California, New Jersey, and possibly Florida and Virginia, where a weak (or in California, nonexistent) GOP Senate candidate could drag down GOP House candidates. There are many other states where there are 1 or 2 endangered GOP held seats.
RCP has placed 15 GOP-held House seats in the lean or likely Democratic column, and two Democratic held seats in the lean or likely Republican column. That accounts for a net 13 of the 23 needed. Add to that 31 GOP-held seats regarded as tossups, and 26 more as Lean GOP. That makes 57 GOP held seats that are tossups or only slight margins for Republicans in which Democrats need to pick up a net 10. There are another 18 Likely GOP seats, which are not really safe this year. Only 6 Democrat-held seats are regarded as tossups. Given these daunting numbers, it is very difficult to see how Republicans hold the House and easier to see a possibility of a significant Democratic gain or 30 or more.