A week after all the ballots have been cast - absentee and provisional ballots as well as those that are machine tabulated -- there are still 13 House races still to be decided.

The reasons vary, but generally, the outstanding votes are from absentee and provisional ballots. Since all of these votes have to be counted by hand, it takes a while. 

Nate Silver's Five Thirty Eight Blog has been keeping tabs on these uncalled races:

As of 2:15 p.m. on Sunday, Nov. 11, news outlets have yet to project winners in 18 races: three for the U.S. Senate, 13 for the U.S. House and two for governor. These races have the potential to meaningfully change the narrative around this election — for example, Democrats could pick up 42 House seats instead of 29, or turn a disappointing showing in the Senate into a draw. 

A common thread runs through these results; many of the outstanding ballots yet to be counted are from Democratic counties:

It’s not unusual for close races in California to still be uncalled even several days after the election. That’s because most people in California vote by mail, and mail ballots only have to be postmarked by Election Day; they can arrive at elections offices as late as three days later and still be counted. Currently, the Republican candidates lead in two of the five districts. However, late-arriving ballots tend to lean Democratic in California, so those GOP leads will probably shrink, if not reverse entirely. (They have already shown signs of shrinking.) Because of this, we’re guessing that Democrats might win most, if not all, of these districts when all is said and done.

[...]

• Although some networks have called the Georgia 7th District, Democrat Carolyn Bourdeaux has not yet conceded and has even indicated it may go to a recount. Republican Rep. Rob Woodall has a lead of less than 1,000 votes with about 1,500 provisional ballots left to count in Gwinnett County and 90 in Forsyth County. (Those are Democratic counties)

[...]

• Democrat Andy Kim declared victory in the New Jersey 3rd District on Wednesday night, but Republican Rep. MacArthur has not yet conceded. As of late Friday, Kim led MacArthur by 3,424 votes, with 6,400 provisional ballots outstanding (they’re expected to be counted by Tuesday). Since most of those provisional ballots are from Democratic-leaning Burlington County, MacArthur’s path to victory looks slim.

[...]

• The New Mexico 2nd District was supposedly in the bag for Republican state Rep. Yvette Herrell — until Wednesday night, when absentee ballots from Doña Ana County unexpectedly put Democrat Xochitl Torres Small into a 1-percentage-point lead. That was enough for the AP to call the race, although our colleagues at ABC haven’t made a projection yet.

[...]

• It’s been a roller-coaster ride in the Texas 23rd District. Republican Rep. Will Hurd initially declared victory, but then a late spurt of ballots put Democrat Gina Ortiz Jones into the lead. Then an apparent error in the vote tabulations was found, giving Hurd the advantage once more. He currently has a lead of over 1,000 votes, but Ortiz Jones says she will not concede until every vote has been counted

Before we jump to conclusions, it should be noted that Democratic counties tend to be urban and more votes are usually cast in those counties than in rural Republican counties, so the vote counting process will be slower. 

But as we've seen in Florida, Democrats believe that rules were made to be broken - especially if by breaking them, a Democratic candidate will get an advantage in a close race. Are similiar shennanigans being pulled in other districts and states? The high profile nature of statewide races for governor and senator in Florida means an inordinate amount of media coverage. But who cares what happens in some obscure district in Texas or New Jersey? The glare of the spotlight is off these races and hence, the possibility exists for fraud.

I'm not accusing anyone of anything. But it is curious that so many of these races are being decided by absentee and provisional ballots that always seem to favor the Democrats. 

Strange, indeed.