Compounding Tolerances and the Senior Who Can't Read

Compounding tolerances.

Every engineer knows what this is, but when a colleague said it to me today, I looked like this...

And then when they told me what it was, I was like this...

Here's what compounding tolerances are, as told by a non-engineer English teacher/tech coach. In any manufacturing process, there is a small but acceptable range of deviation from the norm for each stage of the process. As long as the production in that stage falls within that range, it is essentially within the tolerated specification of quality.

(Hold on. I promise we're going to get to education.)

Within that stage, there's nothing wrong with being a tiny bit off of the specifications. However, when it's a tiny bit off in stage one and then a tiny bit off in stage two and then a tiny bit off in stage three and then...you get the point. You end up with a faulty product. The tiny tolerated deviations compounded into an unacceptable and faulty result.

Just ask Boeing about their 747s right now if you need a better explanation.

Here's why I wanted to jump up and down and scream (in a good way) when this was being explained to me. I finally had a label for my concerns about the way we assess students in our public education system.

Let me explain. Let's for now assume that grades actually represent the percentage of content mastered (yes, this is a big assumption, as most grade books measure compliance more than learning). What grade do students have to get to move to the next grade/course?

A D, which translates (in most cases) to a 60%, meaning that a student can not learn 40% of the material and still move on.

Then the next year, they earn another 60%, and that 40% of content now includes twice as much information. Then that cycle repeats until some poor 12th grade teacher realizes they have a student in their class that can't read. (And then they graduate because we have to ensure that we meet federal requirements and to avoid facing the fact that we have failed this student because we are too stubborn to accept that we embrace a broken system.)

Sal Khan illustrates this perfectly in his TED Talk from 2016. He illustrates the idiocy of this approach by talking about building a house. If you gave a contractor a 60% on the foundation and then moved onto the first floor, where they got a 70% percent (great job!) - when the house collapses as they start building the 2nd floor...is anyone surprised?

Another illustration: as you board your flight, there's a framed certificate on the wall celebrating the fact that this plane earned an 80% when it was built. Unless you have a nice insurance policy and a large gambling debt, you would look like this...

If you need a final illustration, what's your time if you run 60% of a marathon? YOU DON'T GET A FREAKING TIME BECAUSE YOU DIDN'T COMPLETE THE PROCESS.

Okay, I know I've been pessimistic and my tone has been the blogging equivalent of yelling, "Get off my lawn!" while holding a shotgun and a beer.

Here's my point: the effects of compounding intolerances are severe and rampant in our system. So, what do we do about it? I'll break it down at a couple levels.

Teachers:

• Is time or learning more important in your grading system? Because if time is the constant, then learning is the variable. Are you truly holding kids accountable to learning the content entirely?
• What do you consider acceptable? That kid who almost gets it but is a little bit off and we let it slide – guess what happens after that's happened to them for 13 years of education... compounding tolerances. Hold kids to high standards and don't let them cut corners.

Formalized Leaders:

• As an instructional leader of the school, you need to be the most versed person on assessment and grading practices. When someone asks about competency-based education, mastery-based learning, standards-based grading, proficiency-based grading, etc., you should be able to have a meaningful conversation or else the work will never move forward.
• Make people uncomfortable about grading practices that hinder student learning and go against research-based best practice. We sacrifice challenge and growth on the altar of comfort and TTWWADI ("that's the way we've always done it") far too often.
• Have hard conversations at the highest levels of educational organizations about the meaningful foundations that need to be in place before effective teaching and learning can happen. 
• Research the Mastery Collaborative and the Idaho Mastery Education system before you say it can't be done because it already is being done on a large scale in other places. That excuse can't be used anymore. 

I truly believe that this shift could have an incredible impact on how we approach students success and support in schools.

It's hard work, but it is essential to create the most effective educational institutions, which we desperately need in this day and age. Kids deserve it.