media research [@benesch2016counterspeech; @magdy2016isisisnotislam]. @magdy2016isisisnotislam estimate that a majority of Islam and Muslim related tweets posted in reaction to the 2015 terrorist attacks in Paris stood in their defense; an observation also made by @UNHCR-UNGP following the 2016 terrorist attack in Berlin, and supported by our own results (§\[subsec:empirical-results\]).

[**Hate speech and violent events.** ]{} The prevalence and severity of hate hate speech and crimes tends to increase after “trigger” events, which can be local, national, or international, often galvanizing “tensions and sentiments against the suspected perpetrators and groups associated with them" [@awan2015we]. For instance, @benesch2016counterspeech found extensive hate and counter-hate speech after events that triggered widespread emotional response like the Baltimore protests, the U.S. Supreme Court decision on same-sex marriage, and the Paris attacks during 2015; while @faris2016understanding found spikes in online harmful speech to be linked to political events. While these studies are related to ours, they focus on content posted during specific events, or on correlating changes in patterns (e.g., spikes) with events’ occurrence. We focus on broader patterns, aiming to quantify changes across types of events and types of content by applying causal inference techniques.

[**Islamophobia.** ]{} The conflation of Muslims and Islam with terrorism—particularly developed 