How long is a year? How long is a month? What do we do about leap years?

These questions, familiar to any programmer who's ever tested anything, have never been considered by the Wisconsin Department of Corrections, who refuse to do math correctly when computing prison time.

In WI, if you are incarcerated on 1/1 and released on 1/11, you are entitled to 11 days of sentence credit (State v Johnson, 2018). But the troglodytes at the DOC decided that they should just subtract. 11-1=10. This error is super common, especially before 2018.

Inclusive counting is apparently beyond the grasp of the DOC, and it adds up. Some people spend multiple stretches of time incarcerated, and they lose that 1 day of credit for EVERY stretch. This could result in upwards of a week of extra incarceration in some cases.

But that's not all. Let's say you're sentenced to 1 month of confinement, starting on 1/1/2020. Your release date, by DOC math, is 2/1/2020 - which adds up to 32 days of incarceration, which is longer than ANY month. If your sentence began in February, you might "luck out"...

but the effects of DOC rounding often, perhaps *usually*, have bad results for the people serving the sentences. More than that, it's just plain wrong. Math is math. No government agency can have the authority to redefine counting.

The DOC sentence computation sheets would make any nerd vomit immediately. Say you're sentenced to 2 years, 7 months, 16 days in prison, beginning March 5, 2020. The sheet looks like this:

2020-03-15 +
0002-07-16 =
2022-11-1

See the problem?

If you add up from smallest to largest, you don't know whether you're going to end up in a 30 or 31 day month when you're working out the "day" column. The DOC says 1 month = 30 days (which isn't even true on average), so you proceed with that assumption.

Uh oh, this means that your sentence can never end on the 31st of a month. You straight up just get an extra day in prison unless someone catches it (and from what I've seen, the DOC is *not* catching it most of the time).

The 1 month=30 days convention is blatantly abused to extend sentences. Someone incarcerated from 8/1 to 9/1 will be give 30 days sentence credit, despite earning 32 days (one extra from 31-day month, one from the off-by-one counting error).

But someone sentenced to 1 month in prison on 8/1 will spend more than 30 days in prison. The convention is ignored or obeyed on a whim.

The central problem is this: months and years are not well-defined units of time (really neither are days, due to DST, but the State v Johnson precedent allows us to bypass that difficulty). A sentence of years and months needs to be translated into days.

But the agents doing this translation are either careless or malicious (probably both). Days, even weeks, are effectively tacked on to sentences just because the DOC has invented their own ersatz form of addition.

An extra couple of days of incarceration is a big deal. It could be the difference between life and death. Or the difference between seeing your daughter as a free man, or hearing of her death while in prison.

The DOC has no right to arbitrarily extend sentences handed down by the courts. But they do it every time they pull out one of their comp sheets. Few calculations are more important than determining when someone is released from prison, yet careless mistakes abound.

It gets REALLY bad when determining eligibility for sentence adjustments. The calculation requires finding the date at which 75% of the sentence has been served, and the DOC converts between days to years-months-days at EVERY STEP