1. I used districts that had one Republican and one Democrat congressional candidate. In addition to the districts where both major parties didn't run a candidate, I also excluded Louisiana. Louisiana had their jungle primary on election day and the elections had multiple members of one, or both, parties. It wouldn't be an apples to apples comparison.
2. I used the two party vote. This excludes third parties from both the congressional and Presidential elections. This allows a comparison of how Republicans did against Democrats, treating third party voters as the same as those who didn't vote. I did this for consistency. Some races had third party candidates. Others didn't. I didn't include Utah districts because they were the only ones where Evan McMullin got a high percentage of the vote. McMullin voters likely voted heavily for Republicans down ballot, as Hillary Clinton's percentage was fairly close to the percentage Democratic congressional candidates got. So Trump-Clinton numbers would make the districts look more Democratic than they do.
The districts in the first column are those where the two candidates got between 43% and 57% of the vote and the Republican congressional won the seat. The second group are the same Presidential and the Democrat won the seat. The next two groups are the remaining districts where Republicans won and Democrats won respectively. If Hillary Clinton got less than 43% but the Democrat still won it's in the second group.
The first group consists overwhelmingly of districts where the Republican congressional candidate outperformed Donald Trump. That many would outperform him isn't that much of a surprise since all the Republicans in the list won their district. That said I didn't expect that many to outperform Trump and by as much as they do. Thirty-four of them did at least 7 points better. There are a lot of suburban districts in this column. Again, that's not a surprise. Trump got over 57% in many rural districts and Clinton got over that in many urban districts. So those districts are more likely to be in the third and fourth group. A big question for the future is whether Democratic congressional candidates can come close to matching Hillary Clinton in the future.
The districts that Democrats won where Clinton got between 43% and 57% of the vote is smaller. There are more districts where the Republican outperformed Trump, or the Democrat underperformed Clinton than in the group Republicans won. Clinton did win most of these, but it'll be interesting to see if some of these Democrats vote with Republicans in House votes. Their districts are more Trumpy than Republican.