Pew Research published an interesting analysis today looking at online support for Black Lives Matter as measured by the use of the hashtag on Twitter. Pew measured the number of times the hashtags was used, either in support or opposition to the group, and found a substantial shift immediately after the murder of five police officers in Dallas last month:

The weeks (July 5-17, 2016) following the shooting deaths of Alton Sterling and Philando Castile at the hands of police officers represent a highly active period regarding the discussion of the Black Lives Matter movement, as well as the use of #AllLivesMatter and #BlueLivesMatter on Twitter…

Those supporting #BlackLivesMatter generally focused on the deaths of Alton Sterling in Baton Rouge, Louisiana, and Philando Castile in Falcon Heights, Minnesota…

In fact, from July 5 to July 7, fully 87% of the uses of #BlackLivesMatter on Twitter were favorable, compared to 11% that were negative.

However, following the attack on police officers in Dallas that began late on July 7, the tenor of the online conversation changed dramatically. From July 8 to July 17, 39% of tweets using #BlackLivesMatter were opposed to the movement, compared to 28% that were in support and 33% that were neutral.

On July 17, the day the attack on police occurred in Baton Rouge, Louisiana, two-thirds of the tweets opposed #BlackLivesMatter (67%) compared to 26% that were positive and 6% that were neutral.

Pew created this graph to show the big shift in support before and after the Dallas shooting:

At first glance, it appears that some of the people who were supporting Black Lives Matter on Twitter must have switched to opposing them. Some may have done so but it’s also true that many more people were using this hashtag after the Dallas shooting than before. This alternative graph by Pew shows how the number of tweets peaked the day after the Dallas attack:

Pew notes that #BlackLivesMatter is the 3rd most used hashtag related to a social cause (#Ferguson is first). The largest spike in usage of the tag came on November 25, 2014, the day after a prosecutor announced Officer Darren Wilson would not be indicted in the death of Michael Brown.