Reliability and perfection


reliability, n. the extent to which an experiment, test, or measuring procedure yields the same results on repeated trials.

perfection, n. the action or process of improving something until it is faultless.


“There’s a paradox here. Ask most research physicians how a profession can advance, and they will talk about the model of ‘evidence-based medicine’. …[I]n a 1978 ranking of medical specialities according to their use of hard evidence from randomised clinical trials, obstetrics came in last. Yet almost nothing else in medicine has saved lives on the scale that obstetrics has.”

– from The Score: How childbirth went industrial.


I have found myself in a state of slowly trying to procure the most perfect lesson. To fix things up so that it runs minute-by-minute according to a plan, in which I am asking just the right questions, have tasks that are carefully scaffolded at the precise level for each of my students, with every stage of the lesson considered and noted down. The problem with this is that the complexity of the details that I’ve built up in my mind across the 75 minutes of a lesson don’t play out as planned. This, of course, is because I’m dealing with actual people – and young, inquisitive, social teenagers at that.

Instead of needing perfectly tailored lessons they need reliability.


The Apgar Score is a measurement tool that is used in obstetrics. It is a very, very simple tool to administer, consisting of five questions worth two points each. As a result of having this standardised measure used for diagnostic purposes and for comparing the health of newborns, this tool has saved the lives of many babies and their mothers who would otherwise have been at risk of death. And part of the beauty of this tool is that it concentrates on the notion of overall reliability as opposed to the perfect measurement of many characteristics for each and every child.

For an individual doctor, it may seem more useful to work with a detailed tool that goes into the particulars of the baby they are delivering. But consider this one child in the context of all of the babies that are born and how the doctor can learn from the vast numbers of babies and apply that learning to the one individual baby.

If you can gather data on a general population, then as a consequence you will be able to have greater insight into what goes on within that population, including broader patterns or trends, in contrast to the perspective that would be gained by looking at a smaller case study in a greater amount of detail.


Given the simplicity of the Apgar score, it can be delivered by anyone, no matter the level of expertise and no matter the location. The same sort of thinking needs to be applied in schools.

In the complex environment of a school, we are consistently guilty of trying to find the most perfect way of measuring where a student is at or planning a lesson or analysing the performance and progress of a teacher year by year. Now, don’t get me wrong, all of this is important and I don’t deny the utility in understanding each of these insights. However, if we are to better consider the progress of a student and the progress of a number of students overall, then we need to be looking at them as a conglomerate. We need to be thinking, what is a more reliable way in which we can assess improvement and be able to do this in an efficient way?



So I’ve been teaching for a bit over three years now. During that time I’ve begun a journey of building my craft. As a profession, teaching is something where you are constantly accumulating new knowledge and skills. There is no end-point or definitive stage in which you become The Good Teacher.

Some days I am on top of the world. The most difficult student in my class voluntarily spends half of his lunchtime with me doing revision for an upcoming assessment. A former student emails me with the exciting news that she has become School Captain. Another student writes me a note thanking me for teaching her that term. Are those the signs of success? There’s no NAPLAN score or developmental continuum against which these events can be marked, yet they are met with the feeling that some good has been done.

At other times I am low. I think perhaps the job isn’t for me; that I work behind this façade that will soon be removed to reveal that the competence that people have come to see in me is not the reality. This is the case when that difficult student destabilises yet another lesson. Or when I fumble my way through a meeting I am leading. Or when students again let out the disparaging remarks of “I hate maths” – to which, in an attempt to inject humour into the situation, I respond “You’ve just killed a Maths Fairy”. Although, in reality I feel it is a small part of my confidence and my professional image that’s just been killed.

To all this, I’m learning to remind myself that I am doing a good job. There are enough signs around me that tell me this is the case. And it’s not surprising that after a bit over three years of teaching a difficult age-group a subject that is frequently disliked, and within schools where large numbers of students come from families where there is little history of educational attainment, that there are tough days. The idealised image of how lessons will run or the progress that all students will make is just that: idealised.

I recently came across this Humans of New York post that is a nice reminder of the need to put such highs and lows in perspective:

“When is the time you felt most broken?”
“I first ran for Congress in 1999, and I got beat. I just got whooped. I had been in the state legislature for a long time, I was in the minority party, I wasn’t getting a lot done, and I was away from my family and putting a lot of strain on Michelle. Then for me to run and lose that bad, I was thinking maybe this isn’t what I was cut out to do. I was forty years old, and I’d invested a lot of time and effort into something that didn’t seem to be working. But the thing that got me through that moment, and any other time that I’ve felt stuck, is to remind myself that it’s about the work. Because if you’re worrying about yourself—if you’re thinking: ‘Am I succeeding? Am I in the right position? Am I being appreciated?’ — then you’re going to end up feeling frustrated and stuck. But if you can keep it about the work, you’ll always have a path. There’s always something to be done.”

In a job in which you care so deeply about what you are trying to achieve, you need to make it about the work and do so with a tone of equanimity.