This is so useful (now including 4 more years of data):
In the midst of a presidential election tabulation that could take days, with many states showing apparently close margins, it’s worth examining the impact of election recounts. FairVote has published an update to our report, A Survey and Analysis of Statewide Election Recounts, including data on 20 years of recounts, from 2000 to 2019.
Our key finding is that recounts rarely change the outcome of the race, and margins tend to be exceptionally close in order for a change in outcome to be plausible. In the 5,778 statewide elections over the last 20 years, there have been 31 completed statewide recounts. Only three of those 31 recounts overturned the outcome of the race. In all three, the original margin of victory was less than 0.05%.
There have only been two statewide recounts in presidential elections over the last 20 years. The most memorable is perhaps the Florida recount in 2000, which lasted weeks and taught us all the term “hanging chad”. The other presidential recount occurred in 2016 in Wisconsin, at the request of Green Party candidate Jill Stein. Both recounts upheld the original victor and resulted in only small vote shifts. The Florida recount shifted the margin by 1,247 votes and the Wisconsin recount shifted the margin by 571 votes.