Estimating Protest Crowd Size Using the Jacob’s Method of Crowd Counting.

“For many events, especially political rallies or protests, the number of people in a crowd carries political significance and count results are controversial”- Wikipedia

 “Almost everyone who has tried to make a crowd estimate has a vested interest in what the outcome of the estimate is”– Charles Seife, Professor of Journalism and Mathematician at NYU.

Fourth graders applied the Jacob’s method of crowd counting to estimate the protest crowd that gathered in Washington Square Park on Wednesday, January 25th, 2017. The emergency rally was organized in response to President Trump’s executive order implementing a ban on immigrants entering the country from large Muslim populations, including Iran, Iraq, Libya, Somalia, Sudan, Syria, and Yemen.

Getting the Numbers Right: The Jacobs Method of Crowd Counting

Herbert Jacobs, a University of California journalism professor in the 1960’s, devised a basic density rule that has been widely accepted. Watching students protesting the Vietnam War from his office window, Jacobs saw that had gathered on a plaza that was arranged in a grid. He counted those in a few squares to get an average number per square and multiplied that by the total number of squares. He also came up with a basic density rule that states a “light crowd” has one person per square meter, and doubled that for a “dense crowd”. A “heavy crowd” would have as many as four people per square meter, according to this method.

Using People Per Square Meter as Density Factors to Determine Crowd Size.

 

 

 

 

 

 

 

 

 

 

 

Students Estimated Densities by Using an Aerial View of the Protest Crowd, a Scale Diagram of the Park, and Multiplication.

Washington Square Park Diagram Showing Density Arrays.