From Megan McArdle writing at Bloomberg:
[I]f you just enact an employer mandate for all employees, you’ll get into a ridiculous situation where employing a part-time landscaper for a couple of hours a week commits you either to buying him health insurance, or paying a $2,000 fine. That would lead to a lot of black-market activity, and/or unemployment. So, said the bill’s authors, we’ll make it all full-time workers. But what is a full-time worker? Normal definitions are usually anyone who works more than 35 hours a week. Unfortunately, if you set the limit at 35 hours a week, it will be comparatively easy for firms to evade the law by simply having everyone work 34 hours a week. So the law’s drafters sought to make it really, really inconvenient to play those sorts of games by setting the limit very low, at 30 hours a week.
This is related to a regulatory phenomenon that I think of as “building a fence around the law.” I stole this concept from what people who keep kosher call “building a fence around the Torah.” There are a lot of ideas wrapped up in this concept, but one of them is that you take steps to ensure that you can’t break a commandment -- you enact rules that are stricter than the ones found in the commandments, so that you can’t break a rule accidentally, or accidentally-on-purpose. ...
Legislators wanted to make employers offer insurance, without suffering any loss of full-time jobs, so they tried to make it very difficult to accidentally creep into part-time status with a tiny reduction in hours (presumably made up by an hourly wage boost). But this created a different problem: Now if you can’t afford to offer your employees insurance, you have to reduce their hours a lot. Reducing someone’s hours from 35 to 34 can be finessed into an almost unnoticeable inconvenience. Reducing their hours by one-seventh, on the other hand, is going to be noticeable to both employer and employee. ...
