Statistics are often vital to public campaigns to fight social problems. The problem of plastic straws is no exception. Here is how 9-year-old Milo Cress developed the oft-cited statistic:

But as Cress began to dig into research on plastics and the environment, he noticed there wasn’t much data: “I couldn’t find anything on our use of straws in the United States,” he said.

So he called straw manufacturers himself, asking what they estimated to be the straw market in the United States per day. Some gave him a yearly estimate, which he divided by 365.

“Others gave an estimate of around 500 million straws,” Cress said. “That was the number that I stuck to, because it seemed to be around the middle of what they were saying.”…

“Why I use this statistic is because it illustrates that we use too many straws,” he said. “I think if it were another number, it still illustrates the fact that there is room for reduction. That’s really my message.”

Sociologist Joel Best, who has written about the social construction of statistics, could have a field day with this.

With all of the debate regarding this figure, couldn’t someone with expertise in this field offer a number that has some more rigor? Even if the number changes a bit, say it goes down to 200 million straws day, it would not matter much as either figure is huge. And this is the whole point (and this is often the case for advocates against a particular social problem): the big number is intended to shock and spur action.