Letter: Statistical clarity

One thing worse than a misleading statistic is misunderstanding it and restating it as something else. In the Jan. 27 Daily Herald, an article on bail reform stated, "And here in Cook County, which since 2017 has had a policy calling for the presumption of release without bail, those released were involved in 0.6% of arrests for violent crimes.

Another way to state that more clearly would be to say "0.6% of all violent crime arrests were committed by someone on release without bail." Not a very useful statistic unto itself.

Unfortunately, it appears someone took that statement and turned it around into the headline "In Cook County: 0.6% of released suspects arrested on charges of violent crimes." Those two statements are not the same thing. The statement "those released were involved in 0.6% of arrests for violent crimes" is not the same as "0.6% of those released were arrested on charges of subsequent violent crimes."

I believe whoever wrote the headline was misled. A more pertinent statistic would be: What percent of people arrested on charges of a violent crime and were released without bail have been subsequently arrested on charges of another violent crime? That would be a truly useful statistic for an article on bail reform.

Stephen C. Bergeon

Inverness