Lies, Damned Lies, and Educational Statistics

One week till the well-deserved summer break, and I hope all fellow teachers get the opportunity to recharge. Summer does, of course, contain the two results days, which secondary teachers now look forward to with as much anxiety and trepidation as the students. Not least because their pay and career prospects now depend at least in part on the performance on one particular day of a group of largely unpredictable teenagers!

However, I’d go further : their pay and career also depends not just on the actual results of those teenagers, but on the ability of school “leaders” to understand and use data. I don’t know which is more terrifying.

This blog has two parts. The first part recounts a couple of stories of how, in our targets-and-results-obsessive education culture, statistics based on small sample sizes (like your class) can be desperately misleading, and offers a way in which you can defend yourself against overly simplistic statistical judgments about whether you’ve been a “good” or “bad” teacher. The second part goes a bit further and poses the question of whether “good” and “bad” teachers actually exist in anything like the way they are portrayed by media and Ministers, and invites readers to do their own simple statistical search for the “Good” teacher(s) in their school.

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PART ONE

“Facts are stubborn, but statistics are more pliable.” (Mark Twain)

Let me tell you a story which still scars me a bit.

In 2008, we had a particularly horrible set of GCSE history results in my department. I knew it had been a weak cohort, and for two years (since seeing the class lists for the 2006 options) had been warning the Head that the results in 2008 would be grim. Still, after the predictably poor results, much “leadership” followed : interventions, a departmental review, governors’ monitoring. We seemed to have done worse on the A*-C ratio than most other departments. If you’re looking at a departmental A*-C rate of 52% against a school rate of 76%, then it looks bad.

I was frustrated. I’d known the results would be a drop from the previous year (81.4% A*-C, since you ask), but I wasn’t expecting the significant difference between us and other departments.

So, in search of explanations, for the first time I looked at the student level data, rather than the teacher data or the department data. What I found was a bit of an eye-opener: of the 65 students taking history that year, it was the worst result for just 8 of them. For 23 of them, it was their best result. For the remainder, they had scored the same grade in history as they had across a range of subjects. In other words, these specific students we taught had on average done better in history than in their other subjects, yet as a subject, we’d come out worse than most others, and had a real dive in our year-on-year figures. Essentially, these 65 students included a very high proportion of students who got low grades across the board in all their subjects. History was optional, and two years prior to these results, we’d had a poor recruitment take-up from the two Year 9 top sets. As a result, we had a cohort which was less able than the school average. The same students were achieving similar or worse grades in other subjects, but the overall percentages for those other subjects looked better because they also included the higher-ability students who had, in that one year, not chosen history GCSE. Could it be that simple ? It turns out that it could.

The following year, 2009, we had a much more normal ability distribution, and our results returned to normal. The next year, 2010, we recorded some excellent results, and in 2011, achieved more than 90% A*-C. I was receiving pats on the back, one governor congratulated me for “turning things around”, and everyone was happy. Yet the real reason, as I knew full well, was that in 2008 and 2009, the two Year 9 top sets had been taught by a very charismatic young male teacher, and we’d had a takeup of history approaching 80% of our most able 60 students (we’re a girls’ school) ! Since then, dear reader, you will understand that some of my most careful timetabling involves teacher selection for Year 9 top sets….

This was my introduction into how easy it is to misrepresent statistics in the field of spurious school improvement. It was also the first time I started to wonder what difference teachers – including me – actually made. If the results for which we were slammed, or lauded, were actually almost entirely determined by the ability of the students we were in receipt of in any given year, then where, exactly, did that leave these labels of “good” and “bad” ?

So since 2008, I analyse my GCSE and A-level results like this every year (and those of my departmental colleagues). I look at student level data and I try to perceive a pattern. Are they consistently getting worse or better grades in history than in their other subjects? If they were, then I’d have something to celebrate or worry about. But they don’t. One year, I might think we’ve done really well, then the next year, there’d be no similar effect. Yet in each year, we get results at both GCSE and A-level which look very good in absolute terms compared to both the national average and the rest of the school, but also usually in value-added terms on such measures as ALPS. The Department has a reputation of being very strong, and filled with “outstanding” teachers. But even in our best apparent years, where most of our students seem to be recording history as their best or joint-best result, there are always a few who are actually achieving higher grades elsewhere. Our main achievement seems to be being able to concentrate a particularly high proportion of well-motivated, able students in our subject, which means our students are getting high grades. But, by and large, those particular students are also getting high grades in all their subjects. There’s no consistent pattern. Yet there must surely be a consistent pattern if all this talk of “good” and “bad” teachers is to have any meaning.

Let’s be honest, if bad teachers were really like Cameron Diaz, half the student population wouldn’t mind so much

Could it be that students, not teachers, are responsible for students’ exam results?

This stuff matters, because the comparison of teachers so endemic in our schools now is often based on non-comparable datasets. Take another example : in one school I know of last year, the results in one subject weren’t as good as the school wanted them to be. At first glance, simply comparing students’ actual grades to targets, there was one particular class which seemed to have done worse than the others. Immediately, a lot of attention – not all very pleasant – began to focus on the teacher of that class. Had he let the side down ? Was he a “weak” teacher ? Certainly in terms of simple statistics, this teacher’s class seemed to be underachieving.

Yet this teacher understood maths, and did some simple analysis which showed that, yes, there had been a significant number of students in his class who had undershot their target for his subject. But those same students had also undershot their targets across ALL their subjects. In other words, their performance in his class was entirely consistent with their performance in all their other subjects with all their other teachers. It was the students who had underachieved, not the teacher. Yet because a significant group of these underachievers happened to be concentrated in his class, his overall results seemed poor. Coupled with the culture of ranking teachers on a scale of “good” to “bad”, and the national narrative which consistently asserts that the main determinant of student outcomes is the teacher’s inputs, his reputation, his pay, even his career, was under threat – yet the evidence was very clear that his impact on those same students was the same as the impact of other teachers in the same school who were being congratulated for their strong aggregate performance. That teacher experienced last year what I experienced as a Head of Department back in 2008 – the way in which statistics can be misused and misinterpreted to produce inaccurate and damaging conclusions.

And this sort of statistical ignorance is becoming institutionalised. For example, I was shown some new SIMS software only last week (a data manipulation package which many schools use), which the Capita trainer said would allow me to “compare the effectiveness of my teachers” by sticking a numerical value on the collective difference between their students’ target grades and their absolute grades. The teacher with the biggest number must be the best, right ? Except they’re not teaching the same kids. What if that teacher with the biggest number just happened to have a class of students who were performing highly across all their subjects, while the poor bugger with the lowest number had a high concentration of consistently low-achievers across all their subjects? That numerical value in fact has no value at all. That won’t, however, stop it being used to wrongly and unfairly label or rank teachers, if it falls into the wrong hands.

So my recommendation to all colleagues, following the results, is to do this self-same student-level analysis. I also strongly urge school “leaders” to show the same degree of interest in the statistics. It’s not hard to do, takes only a few minutes, and ultimately, if you genuinely wish to compare teacher performance, then this is the only reasonable way to do it.

At this point, if all you were interested in was a handy backup plan in case your superficial results look a bit ropey in August, then you can stop reading. Best of luck to you and I hope your results are great.

If you’re still not bored beyond belief, and are interested in a bit of flash-mob crowd-sourced research, then read on….

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PART TWO 

Do “good” and “bad” teachers actually exist?

“Hang on,” I hear you cry, “What if I do this student-level analysis of yours and then find out that actually the students are all achieving less in my class than they are in their other classes ?”

Well, that’s a theoretical possibility. It’s entirely possible that the reverse of the effect described above is actually happening : you could have a class or department recording stellar results, for which everyone is congratulated, but a student-level analysis might show that those students are all very high achievers across the board, and are actually notching up their lowest results in your subject – a fact hidden by the concentration of high-achievers in your subject.

I would offer this reassurance, however : I don’t think you’ll find that. What I think you’ll find is that there is no consistent significant difference in same-student performance across different subjects. Mind you, I’m basing that on my own analysis of my own school’s results, and I’m fighting hard to retain an open mind that other schools may actually turn up statistical differences. I’m not going to claim that I’m right and the entire educational establishment is wrong; I’m not Gove. Nevertheless, I put it to you, dear reader, that it’s quite possible that there’s actually no range of teacher quality in your school. There’s simply a tiny minority who are catastrophically bad, and the vast majority who are what we in England might call “fine”, and whose impact on individual student results is actually pretty similar.

 Are both left and right united in error ?

That’s quite a bold statement, I know. After all, don’t Ministers, journalists and Wilshaw line up every week to tell us that the main determinant of student outcomes is the quality of the teacher ? Only last week, Nicky Morgan launched a broadside in the Daily Mail at “coasting” schools, and Wilshaw’s regurgitated some of his favoured old themes about teachers “failing” white working class boys. While from the other side of the spectrum, Gaby Hinsliff wrote a piece about the glass floor through which wealthier parents protect their offspring’s privileged position, to follow Will Hutton’s Observer piece from a couple of weeks ago about the schools system. These commentators encompass both ends of the political spectrum, and they differ significantly on what schools policy should be. However, they’re all based – along with nearly every article, speech or public statement a politician or journalist ever utters on education – on one basic premise : student outcomes are directly related to teacher “quality”.

“Good” teachers produce “good” results, either for your favoured Disadvantaged-Group-Of-The-Moment, or for all students. This analysis then extends seamlessly from individual teachers to schools, producing “Good” schools and “Bad/Coasting/Failing [delete as appropriate]” schools. The prescriptions for how to deal with low student exam outcomes almost always involves some element of replacing “bad” teachers with “good” teachers, resulting in a “bad” school becoming a “good” school. Often, the only difference between the prescriptions of right and left is that the right tends towards the view that you simply sack the “bad” teacher and recruit a “good” one instead, whereas the left has a more optimistic view that all teachers can become “good” through CPD/research/support and so on.

At the moment, we have an interesting inconsistency, particularly on the left, where I suppose my general philosophical position usually resides. On the one hand we decry the Government’s cack-handed attempts to elevate some teachers above others, and OFSTED’s institutionalised desire to label some schools failures while lauding others. We argue this is unfair, as such judgements rarely take into account context, and so on. Yet on the other hand, we cling ferociously to the idea that teachers DO make an important difference. Logically, however, if we accept that teachers do make a significant difference, then we have to accept that there will be a range of difference made. This means we’re buying into the very same concept of the “good” teacher and the “bad” teacher which the Government promotes, and upon which nearly all its policies are based. It doesn’t matter if you don’t think such characteristics are fixed, and you want to label that more kindly as the “good” teacher and the “will-be-better-after-CPD” teacher; you’d have to accept, if you think teachers make a difference, that there will be degrees of difference – a scale of effective to ineffective, if you like. To do otherwise would be inconsistent and illogical. Hopefully you’re still with me.

At this point, it may seem like I’m about to start wheeling out that hoary old chestnut of “A good teacher can get 1.5 years of learning growth; a bad teacher gets half a year of learning growth”.    I’m certainly not. Jack Marwood, my favourite blogger, demolished this myth some time ago, and his series of blogs on this subject should be compulsory reading for everyone in education.

Policy Exchange receiving instructions from DFE for their next Free School Impact report

What if everything you ever thought was wrong ?

What if that basic premise is wrong ? What if the reality is that the difference that nearly all teachers make to a student’s outcomes is actually pretty similar no matter what the reputation of the teacher. Or marginal. Or even non-existent. That would be a pretty uncomfortable thought. Because if it were true, once teachers had stopped happily shouting “You can stick your PRP up yer bum!” at the Government, we might have to have a moment of reflection and think – err, hang on…? Who wants to be the guy or gal who doesn’t make a difference? Fortunately, there’s an entire industry of commentators, gurus, authors, “leaders”, trainers, and motivational sign writers who are out there to tell you that there is indeed a “good” and a “bad”. And we can all aspire to endlessly “improve”. Hooray !

Yet….yet…yet… I worry that the reality on the ground doesn’t seem to support the universal narrative. Of course, it’s very hard to make comparisons between schools because of the different contexts – different peer groups, different timetables, different curricula, different cultures and, crucially, different students. So comparing student outcomes for a maths teacher in a suburban Grammar school with one in a tough secondary modern would be crass and stupid. As such, it’s generally something only the DFE and Ofsted do, so we can discount it. All the studies which purport to identify teacher impact try their best to remove external factors such as socio-economic background, school type, subject differences and so on from the equation – trying to isolate that elusive “teacher factor”.

But while I can see how such comparisons can be made on a grand scale involving tens of thousands of students simply because weight of numbers should iron out statistical oddities, I don’t see how they can be made at the level of the individual teacher, because individual teachers will generally only be teaching a very small number of students in any given year, and are thus prone to something which no study could ever entirely eradicate in such a small sample size – what we might call “The Adolescent Effect”, or “Immature Human Agency”. Frankly, you can call it what you like, but anyone who tells you that this group of 30 teenagers will always respond in the same way to the same inputs as that group of 30 different teenagers has probably never met a teenager. Any study which tries to consider individual teacher effectiveness based on different teachers teaching different groups of students is thus automatically flawed beyond hope, in my opinion. You’re simply not comparing like with like – just as the examples I gave above didn’t – they’re different kids, with all the random variations which individual adolescent humans bring to the table; the annoying, loveable little buggers that they are.

However, every year, we actually have a national data set which compares individual teachers’ impacts on hundreds of thousands of individual children who have been through the same school, same culture, same curriculum and so on: we have the data from each and every secondary school. There is thus a way in which we can all use some fairly easily accessible data to establish whether – at least in each individual school – there’s hard evidence of this spectrum of teacher quality. I’d thus like to invite readers to use the statistics from their own schools to see if they can identify these “good” and “bad” teachers. Imagine if we all used our results to try and locate these creatures, but couldn’t ? That would throw a cat in amongst the pigeons, given that nearly all educational policy is based on their existence. Or alternatively, you might find them, and you can play a fun game of “Are the actual top teachers the same people my SLT think they are?”. Come on, we all want to play that game.

I’ll apologise to primary colleagues, as this will inevitably be very secondary-focussed.

 “Contrariwise,’ continued Tweedledee, ‘if it was so, it might be; and if it were so, it would be; but as it isn’t, it ain’t. That’s logic.”

Let’s start with a logical statement :

If “good” or “bad” teachers make a difference to outcomes, then the same children taught by “good” and “bad” teachers will get different results.

That seems to me to be logically unarguable. This is the basis upon which nearly all current education policy is built. Either recruit or train the “best” teachers, and your students will produce the “best” results. If you allow the “worst” teachers to stay in post, or fail to improve them, then your students will get poor results. If you accept that the same students get the same results with “good” and “bad” teachers, then in what sense are those labels valid ? They wouldn’t be. So we need to find evidence which supports this teacher effect.

So, logically, what we would expect to see in any given school – if the statement above is true – is that each student will have a range of results: higher results from the “good” teachers, and lower results from the “bad” teachers. However, we need to go further : if teachers make a difference, then we would expect that the results of a “good” teacher’s students would be consistently better than the results of a “weak” teacher’s students. Or at least consistently statistically significant. If “teacher quality” was the main determinant of outcomes, and “teacher quality” differed significantly, then we would expect to see a simple graph which went something like this :

Figure 1 As teacher “quality” rises, so does student achievement

The numbers bit

So can we identify strong or weak teachers through results – as everyone and their dog states we can, repeatedly? The answer is that we should be able to, if they exist, using student-level data.

Here’s an example data set from one teacher – me. I am thought of in my school as a “good” teacher (I suspect AHTs and above would also add “but a pain in the arse”, but that’s not pertinent to this exercise right now). The annual figures for both A*-C and A*-A are WAY above the national average both for my personal classes and for my Department as a whole. In theory, based on a simplistic comparison of my results with history teachers in other schools, I am a very “good” teacher. This would be a bogus statement, however, because I teach a school intake which is of above average ability compared to the national cohort, although it lacks much of a very top end because of the existence of local grammar schools. So my overall results compared to national averages mean nothing at all. I’m not “good” yet.

Still, within the school I teach the same GCSE and A-level students as numerous other teachers. If our earlier statement about the effect of differing teacher quality is true, then we should logically expect me to fit somewhere on a spectrum of teachers, ranging from least to most effective.

So let’s have a look. All anonymised, of course, but these are real results from a few years ago. I’ve only included subjects which are largely written, largely externally examined, and excluded those which only a very small number have taken (eg Russian for our native Russian-speaker). I accept that different subjects are of different ability levels, but again, if we apply logic and say that one can’t compare across subjects, then what in God’s name are we doing talking about “good” and “bad” teachers in the first place, and what the hell is PRP all about ? Given that the entire range of education policies based on the notion of differential teacher quality is predicated on the idea that exam grades in different subjects are comparable, I feel that we may as well use that in our search for the “good” and “bad” teachers.

So what patterns jump out ? I did really well with student J – hooray for me, give me a performance related pay rise! But don’t look at students I or R. And damn you, Chemistry teacher, for getting a better result with student Q, but eat my historical dust, mathmo, when it comes to student L !

It’s not obvious, is it ? Let’s try a more recent year.

God, look at student E – I suck. Oh, hang on, don’t look at student E, look at student G – I’m still great!

There’s not really a pattern emerging here in terms of teacher impact. I could post more tables, but frankly, I think everyone would get very bored. You can take it from me, however, that all the GCSE and A-level data from my school over the last seven years show the same thing. Incidentally, so do the AS and A2 tables, although those are slightly more difficult as there are fewer subjects per student to compare, and greater diversity of choice.

In other words, there is no evidence of any teacher effect at all in my school. The students I teach get broadly the same results in my subject as they do in all their subjects. Some do better elsewhere, some do better with me, but there’s no consistent pattern.

This might just mean I’m mediocre, of course. Maybe I’m a “coasting” teacher. But then you’d have to apply that description to all my colleagues in the history department, as our individual and collective results are all indistinguishable. And I’ve also done this for other colleagues in other departments (yes, I am competitive, and yes, I was looking to see if anyone was doing better than me). However, my search turned up nothing of significance in comparable subjects. There just isn’t, in my school, any evidence of differential teacher impact. Logic thus requires me to reach the conclusion that there aren’t any significant differences in teacher quality within my school.

It’s the kids, innit?

However, if no pattern is discernible amongst the teachers, one pattern does appear, though, and it’s not one which particularly supports the general idea of “good” and “bad” teachers. If you look at the results above, you have 33 individual students, whose only connection is that they all happen to have been taught history GCSE by me. I could have given you many, many more, but nobody wants to look at endless lists of stats (well, maybe Jack Marwood does, but it’s something of a minority interest). Now look at their grade distributions. There is a remarkable consistency of grades across all their subjects. Most students’ results “cluster” around a certain level. You have A*/A students achieving those grades across the board, with maybe a solo outlier B. You have “Mostly B” students with the odd A or C. You have the occasional C/D borderline student with results either side of that line. There aren’t so many students achieving lower averages because they don’t tend to choose history for GCSE. Give the compulsory Ebacc a couple of years, and I’m sure I’d be showing you their similar new grades in the lower numbers.

These grades are not all the same, of course. It’s not uncommon to see a “cluster” of grades around a certain level, with a couple of outliers. Aha ! You might cry – there’s the evidence of good and bad teachers – the high and low grades. Except, of course, this is not replicated consistently. If these outlier grades were related to the teacher, then logically you’d expect to see a consistent pattern of the History grades always being the best or joint best, or always exceeding English, or vice versa. Take the second table above, and look at students A, B and D. These three students were essentially B/C borderline students, with their results clustered around those two grades. For student A, history was her joint worst result. For student B, it was middling, while for student D, it was her highest result. You can see a similar pattern amongst A/B borderline students in the first graph – sometimes History is their best or joint best result, sometimes not. I guess that makes me an outstanding, coasting and ineffective teacher. This pattern repeats itself across all 200 or so students who take GCSEs in our school every year, across all similar subjects.

In other words, by far the strongest determinant of outcomes in any given subject – in my school at least – is not the teacher, but the student. Students tend to have a general level which they’ll achieve across the board give or take some oscillations, and there’s no evidence of any consistent teacher impact on those oscillations. It may be that they just put more effort into a subject they liked more, or that they just “got” that subject more, or that they simply had a bad day on the day on which that subject’s exam was held. The inconsistent nature of the differences suggests pretty strongly that, logically, those differences are much likely to result from a factor intrinsic to the student, rather than an extrinsic teacher factor. Exam results, it turns out, are much more likely to be related to the students than the teachers. Who knew ?

 

Yes, yes, I know, not all of them are like this.

But…but…but….

There are, of course, some valid objections to this sort of comparison. Are all subjects of equal difficulty ? No, of course they’re not. So just because a student gets an A in Geography doesn’t mean that their teacher was better than the maths teacher who taught the same student to a B. I accept that, but when you look at data sets with this many results over such a long period, even those differences in subject difficulty can be eliminated, because you should expect to see consistent patterns: if Geography is a grade easier than maths on average, then the “good teacher” will be visible because their results are more than a grade higher than the maths teachers’ grades, and so on. It’s not there, though. It’s never there. In fact, I’d go further : these subjects have very different inputs. Prior to GCSE in Y11, students will have had FAR more maths, English and Science lessons than history lessons. They’ll have had far more “interventions” of the extra-lessons-in-the-holiday variety in some subjects than in others. Yet despite all these differences of inputs from school or teacher, which you’d expect to show up in the results, they don’t. That pattern of clustered results with fairly random outliers still holds : it doesn’t seem to matter what inputs are brought to bear in terms of time, attention, “extras”, priority etc; the A students get a bunch of As, the B students get a bunch of Bs, and so on.

Another objection might be that not all students take the same GCSEs, and those kids who all have the same history teacher might have two different English teachers. Maybe the history teacher is worse than one English teacher but better than the other ? This is a bit of a clutching at straws argument, but it’s valid. Yet we’re looking for patterns here. If we follow our logical statement above, then somewhere in every school there is a teacher who consistently has her students achieving their best grades in her subject, and there should be some poor soul whose students consistently achieve their worst grades. To accept otherwise would be to see teacher quality as an unending game of rock-paper-scissors, where English is better than Maths, and Maths is better than History, while History is better than English. And where on earth would that leave our supposed straight-line spectrum of teacher quality upon which our entire educational policy edifice sits ? So our logic requires us, despite objections, to be able to identify those teachers who are consistently seeing their students achieve their best or worst grades in their subject. I can categorically state that, at least in my school, such a person does not exist.

A third point worth noting is that these grades are of course based on raw scores and moving grade boundaries, and in the more subjective, literate subjects, are at serious risk of mis-marking. This could in theory reduce the value of this data as a comparative tool. But that takes us back to the point I made earlier – if we accepted that the data is so ropey that one shouldn’t draw conclusions form it, then that rather makes the whole concept of “good” and “bad” teachers redundant anyway, because there’s be no reliable way of measuring impact at all.

Anyway, the graph of teacher input to student output in my school, when student-level data is considered, essentially seems to go like this :

 

As teacher quality rises, so….oh….hang on….

All that’s left is to suggest my school is itself a statistical outlier. All our teachers are of similar standard, which is why we are an “outstanding” school. Well done to us for having recruited/trained such an excellent collection of similarly brilliant teachers. Hmm. Firstly, I don’t think my SLT think that when they look at me. Secondly, that’s a fairly remarkable achievement, because while the teaching workforce in my school is more stable than many, there’s still been a pretty substantial turnover of staff over the seven years since I started crunching these student-level numbers. And that fundamental pattern of no discernible teacher impact has been consistent for those seven years, whether the teachers are young, old, PGCEs, SCITTs, experienced, inexperienced, male, female, blobby, Govian, whatever. The school encompasses teaching styles which vary dramatically, lesson time allocations which differ considerably, and course changes which differ from subject to subject. All the disruption and change of the last seven years which all schools have had to deal with. But not once, in all that time, with all those exams and all those teachers, has a single teacher effect ever been discernible when you search for actual consistent differential outcomes at individual student level. Hmm. Hmmmm. Hmmmmmmm.

Crowd-sourced research

I have to accept that this last point may be true. It may be the case that all teachers in my school are equally great, or mediocre, or bad. But differential good and bad teachers must therefore exist in other schools if education policy is not to be a nonsense. And it’s easy to discover if they do. Any secondary teacher has access to their school’s GCSE results. So I’m inviting all readers to do this same data crunching.

• First, have a look at your GCSE results, and see if you have the same “clustering” of results on an individual student basis around a certain grade range. If you actually have a fairly common wide distribution of grades at the individual student level, with quite a lot of students achieving a broad range of results, then you probably have good grounds for hope that you can identify some “good” and “bad” teachers.

• Second, identify students taught by a single teacher (probably tactful to do yourself), and look at their results across the board. Are that teacher’s students consistently achieving their worst or best result in that subject ? If so, then you may have identified a “good” or “bad” teacher. Although you might want to then check another couple of years’ worth of data just to make sure it’s not a one-off fluke.

• Third, post your outcomes here (don’t name the “bad” teachers, for the love of God !). I’m genuinely interested. Like all of us, my own views are heavily influenced by my own experiences, and so that experience leads me to conclude that there’s not a whole lot of support for the concept that teachers are “bad” or “good”. I’m open to the possibility that somewhere out there, there is statistical evidence that there are teachers whose students always do worse or better for them than for other teachers, in subjects of comparable nature. So let’s see it.

By the way, I expect that it should be possible to identify the occasional “catastrophic” teacher. You know, the guy who teaches the wrong course for the exam, or the one who is so incapable of classroom control that all of his students think they’re actually studying “Desk Jumping and Spit-Ball Lobbing” on Period 4 on a Wednesday. My school just doesn’t have any of those walking disasters, although a very long time ago, when I joined the school, we did have one (loooong since departed), so I accept their existence, if not in the numbers which the media seem to believe. So I think in less fortunate schools, I’d expect to see the occasional teacher whose students’ results are consistently the worst results ALL of them get. What I’m interested in, though, is whether it’s possible to identify that star teacher, the woman whose students always get their best results in her class, year on year. It’s THAT teacher I can’t find in my school. See if you can find him or her in yours.

And if, of course, you don’t want to wait until this year’s results, there’s nothing stopping you digging out 2014’s statistics to play with in that period where you used to have a Y11 class….