From Professor Doug Berman’s Sentencing Law & Policy blog: “The question in the title of this post is the heading of this new posting at the Prison Policy Initiative building off the the group’s recent big report Arrest, Release, Repeat.  Here is part of the set up to the latest state-by-state data analysis (which requires a click through to see in detail):

County and city jails have been called “mass incarceration’s front door,”but campaigns to reform or close jails often don’t receive the attention they deserve. Why? Because the traditional way we measure the impact of jails — the average daily population — significantly understates the number of people directly affected by these local facilities.

Because people typically stay in jail for only a few days, weeks or months, the daily population represents a small fraction of the people who are admitted over the course of a year. But the statistic that better reflects a jail’s impact on a community — the number of people who go to jail — is rarely accessible to the public.

Thankfully, we can now get close to closing this gap in the data and making the impact of jails clearer.  Building on our new national report Arrest, Release, Repeat, we’re able to estimate the number of people in every state who go to local jails each year.”