The Science Behind Crowd Size Estimates Is Complicated by Politics and Privacy

The question of how many people attend a large event like Joe Biden’s presidential inauguration, or a Black Lives Matter march, may appear to be a simple one. But even with a standard method for estimating crowd sizes that dates back to the 1960s, the calculus can be tricky — and political. NBCLX’s Fernando Hurtado explores how technology is making crowd size estimates more exact — and raising thornier questions about privacy.