Short answer
It lifted them, but not ahead of the polls. Radical right pages drew about 47% more interactions per post than other pages in the same country and month in September and October 2015, but Facebook did not clearly move before the polls did.
What the evidence shows
- The study compares 15 populist radical right party and leader pages in nine European countries with 68 other party and leader pages in the same countries, month by month from July 2014 to June 2016.
- Compared with January to April 2015, radical right pages drew about 47% more interactions per post in September and October 2015, and about 26% to 42% more in later periods to June 2016.
- A smaller rise in July and August appears in all posts but not in link posts, so the change is clearest from September, at the height of the crisis rather than before it.
- Radical right pages did not post more, and other populist pages saw no similar rise.
- Comparing parties' shares of Facebook interactions with their polls in six countries shows no consistent order: Facebook moved earlier in Hungary and Flanders, at the same time in Norway and Slovenia, and later in Sweden.
Caveats
Estimates are smaller without the pages whose classification is most disputed, and because CrowdTangle's capture of photo posts rose sharply in May 2015, pages are compared within the same country and month.