Years ago my college roommate embarked on a several-months-long exercise mooning over a guy whom I, her roommate, was treated to endless melting expositions regarding his exquisite qualities.

Imagine my own excitement when following the amazing happenstance of their actually meeting and liking one another, I was at last allowed to meet this paragon.

And now just try to envision my own existential mind-shock upon encountering this Adonis and finding him utterly, … well, unattractive. Not a twinge, anywhere. He was, not to put too fine a point on it, one of the singularly least attractive specimens I had ever laid eyes on. If I had not lived through these six months of thorough besottedness, I would have believed this a joke, a ruse. And yet the scene resembled nothing so much as something from Shakespeare’s Midsummer Night’s Dream: this guy was as attractive as an ass.

So what is a Good Teacher? What makes a Good Teacher? Who says it’s any different from whatever makes for a Gorgeous Lover?

Relationships are two way streets, and that goes for the relationship between a teacher and a pupil too.

I wish I had a penny for all the conversations I’ve overheard between parents in which one regales another with tales of how unutterably execrable a certain teacher was for their child. I have been warned off more teachers than I care to recall who then, as it happens, it turns out that I actually found quite engaging, sometimes even superb.

The thing is, I do not disbelieve these others’ tales. I think they are true. For their child, for them, for my roommate, this other individual was a problem, or was fabulous … whatever. For them, that relationship was as it was recounted. This does not translate to my (or my child’s) relationship being the same.

And it’s a good thing, that. Because as has been famously remarked: There’s Someone For Everyone. This is as true for mates as for teachers. People are complicated systems and not linear equations. The inputs of excellence are many, and varied and interdependent. Time figures as well as personal “chemistry” and style and so many other parameters, known and unknowable, it just cannot all be quantified, anticipated or mapped.

How else to conclude that one of the teachers highlighted in Vergara as “grossly ineffective” was deemed “teacher of the year”? At least some people according to some set of metrics considered that teacher not only not bottom-of-the-barrel, but cream-of-the-crop.

These “value-added-measures” being promulgated as metrics of teacher education violate the very axiomatic rules of developing a metric: robustness. You have to be able to count on the metric producing the same answer from year to year, under varying conditions that ought not to affect the outcome. Say, a different set of classroom students or a different year or a different summative assessment. If what you’re measuring is “teacher excellence”, then that metric needs to be robust to independent parameters, say, a child’s home-stressors, or poverty or parent’s educational status, etc. It’s not that these parameters are not important, but they need to not affect this purported metric of “teacher excellence”. Else this metric is not measuring what is being claimed if it does not produce an answer that is addressing that teacher’s excellence, and only that teacher’s excellence.

But this is never going to happen because just like it is true that my roommate was deeply affected by her Adonis while I was not, there are teachers who will be excellent for some pupils while yet performing precisely the same way for others for whom their performance will not be excellent.

There is no such thing as an excellent teacher for one and all because their students are not one and the same.

And so how are you going to control for that sort of difference? Who’s to say my roommates’ dream come true was not a True Swan? Who’s to say that “excellent teacher in front of the class” is really that?

And therein lies the problem with Vergara. It’s all very well and good to remove “ineffective” teachers (check out the hundreds of comments), but what if that is an unrealizable concept? What if this is not only a concept that is impossible to define, but unlike pornography is not even a concept that you know when you see it? What if you think you may know it, but you are wrong?

Where is the authority to challenge the eyes of the beholder??