STEM students are familiar with the idea of a “weeding course” or “weed out course” where their goal seems more to filter out “students unfit for a field” rather than teaching knowledge. Indeed, I talked to fair amount of people who think that weeding is an important responsibility for universities and professors, to save everyone’s time.

There are several reason that I despite this mindset. First, many so-called “weeding courses” are simply examples of poor teaching. And then the lecturers retroactively justify their incompetence as a deliberate attempt to “weed out” students. I’ve experienced these so-called “introductory” courses firsthand, where the teaching was so inadequate that you needed substantial prior knowledge just to pass. And when you do have that background, the content being taught become useless anyway.

Second, the “weeding” process disproportionately affects underrepresented groups, who are likelier to lack prior knowledge and skills. Weeding just feeds the vicious cycle for people to claim that those groups are intellectually inferior and unfit for STEM.

Then there’s the argument that only passionate and motivated students deserve to remain in STEM. The thinking goes, “If you’re not interested in your field, why pursue it?” And supposedly, weeding is a way to filter out those who lack enough interest. While passion is certainly a good thing, most people don’t have an intense passion for their profession. Yet, they can still perform their jobs effectively—sometimes even better than those of us who are deeply passionate, who often let our strong opinions and passion cloud judgment and priorities. I, for example, am much happier doing my personal projects than doing things that need to be done.

What should lecturers do instead of relying on weeding? While it’s true that students who are significantly behind can slow down a class, intentional poor teaching isn’t the solution. Instead, they should clearly outline the prerequisites at the start of the course, make the level of difficulty obvious early on so students can make an informed decision to continue or drop the class, and provide options for those who need to revisit the basics.