Performance evaluation of teachers

From the AER:

…observable teacher characteristics like graduate education and experience are not typically correlated with increased productivity [among teachers]. Many researchers and policymakers have suggested that, under these conditions, the only way to adjust the teacher distribution for the better is to gather information on individual productivity through evaluation and then dismiss low performers. This paper offers evidence that evaluation can shift the teacher effectiveness distribution through a different mechanism: by improving teacher skill, effort, or both in ways that persist long-run.

We find that teachers are more productive during the school year when they are being evaluated, but even more productive in the years after evaluation. A student taught by a teacher after that teacher has been through the Cincinnati evaluation will score about 10 percent of a standard deviation higher in math than a similar student taught by the same teacher before the teacher was evaluated.

our estimates indicate that postevaluation improvements in performance were largest for teachers whose performance was weakest prior to evaluation, suggesting that teacher evaluation may be an effective professional development tool.

Not a surprising result but it’s always nice to have the empirics to back up your assertions.

Should student loans be bigger?

I share Holly Walker’s concern about the plight of post-graduate students. She is disturbed by a new survey showing that

[post-graduate students] committed to finishing their study highlight[ed] concerns about being able to provide basic needs for themselves without access to the [recently cut student] allowance, such as food and shelter.

As Matt has discussed previously, it is hugely unfair that students do not enjoy the same safety net as the rest of society when they struggle to find employment during their studies. If they are making a genuine effort to find part-time work during their studies, they should have access to a benefit or allowance, just as anyone else does.

The more important question is whether they should be supported through their studies even if they choose not to engage in part-time work. In that case I don’t see a convincing rationale for providing free support to students. They are voluntarily investing in their human capital in anticipation of better opportunities for themselves in future. As we have discussed previously

[t]hree years after completing their degree, a bachelor’s graduate will earn 51% more than someone with only secondary qualifications. Someone with a master’s degree will earn 74% more and a doctoral graduate 120% more.

It makes sense that a person would invest in education to take advantage of those wage increases, along with all the other benefits of a tertiary education. However, it is hard to justify forcing the rest of the population to pay for their personal investment that they benefit from so greatly. Nursing school scholarships may be a good alternative for those wishing to save a bit.

Nonetheless, some people find it hard to raise the money to attend university, despite the likelihood of higher future earnings. That is why we have a student loan scheme. If students are finding it difficult to pay their way during post-graduate study then it probably means that they are unable to borrow enough during their studies. That is because student borrowing is extremely expensive for the government, so the government limits its liability and costs by capping the level of borrowing. A simple solution would be to re-introduce interest on student loans, since the interest comprises the majority of the government’s cost of lending. That would allow the government to lend out more money to students at a lower cost.

Through that change we could allow students to live more comfortably during their studies, and ensure that the transfers to those, relatively wealthy, individuals do not become inequitably large.

The moral imperative of amoral theorising

Luigi Zingales:

Oddly, most economists see their subject as divorced from morality. They liken themselves to physicists, who teach how atoms do behave, not how they should behave. But physicists do not teach to atoms, and atoms do not have free will. If they did, physicists would and should be concerned about how the atoms being instructed could change their behavior and affect the universe.

My colleague Gary Becker pioneered the economic study of crime. Employing a basic utilitarian approach, he compared the benefits of a crime with the expected cost of punishment (that is, the cost of punishment times the probability of receiving that punishment). While very insightful, Becker’s model, which had no intention of telling people how they should behave, had some unintended consequences. A former student of Becker’s told me that he found many of his classmates to be remarkably amoral, a fact he took as a sign that they interpreted Becker’s descriptive model of crime as prescriptive. They perceived any failure to commit a high-benefit crime with a low expected cost as a failure to act rationally, almost a proof of stupidity.

The problems of measurement in education

The Dim Post has a great guest post up that demonstrates what researcher drily refer to as ‘ability bias’. I’m not going to reproduce it all here but it’s worth reading if you’re not familiar with the problem.

The bit that I find really depressing about the article is this:

So, after all this has been done, Ministry Faktdrones come in and look at one piece of paper that has all of our grades on it. They don’t look at the students as humans, don’t look at any of our processes, and often don’t even look at previous results which would let them know things like value-added results. They look at one sheet of results and say “Look here – the class with 30 all got Achieved, and the class with 15 all got Achieved too. That means, statistically, class size doesn’t make a difference. Let’s cram forty of the little firestarters in there next year!”

Something I constantly and tiresomely have to harp on about when I’m talking to (at?) people about this and other education issues, is that the students are not statistics, and sometimes can’t be pigeonholed to fit a statistically clean model.

I’ve worked with people in the Ministry of Education’s research division a fair bit and they’re all hugely knowledgeable and competent people. They’re well aware of these problems with the statistics and highlight them in their research papers. They even work with the people who gather the data to try to improve the way it’s collected and overcome some of the measurement problems. So why do teachers still perceive Ministry researchers as ‘Faktdrones’? Either the research is being poorly interpreted by the policy teams or the outcomes of the research are being poorly communicated to the teachers. Possibly both.

Whatever the problem is, the author’s response seems to be to reject the use of statistics to inform policy because “students are not statistics”. Unfortunately for the author there is unlikely to be a reduction in the reliance on statistics to determine policy. From what I can tell the trend is actually for more statistics. Given that, the solution to problems such as ability bias is to collect better data. Sadly, the experience of teachers such as the author of this piece is likely to deter them from helping researchers interested in collecting more detailed data about their students.

In policy circles people often say that some data, however rough, is better than no data at all. Unfortunately, a little bit of data coupled with a little bit of knowledge can be a very dangerous thing. If it causes practitioners in the profession to be alienated by policy makers then it may actually be detrimental. It’s sometimes hard to remember that the ultimate goal of research is to help the people being studied, not simply to study them and experiment for its own sake. At times that may require a bit of caution and restraint.

Why I’m not worried about struggling students

The recent budget reduced the number of students who are eligible for the student allowance, particularly for postgraduate students. There have since been almost daily articles in the newspapers lamenting the students’ plight. Today there is an article in which a student describes how she will have to take on extra debt to finance her postgraduate education. Similarly, my Facebook is full of people wondering why the government refuses to ‘invest in our future’. The reason is fairly straightforward: when the government pays for tertiary education it transfers money from poor people to wealthy people. Tertiary students, particularly those in postgraduate education, are some of the wealthiest people in our society and don’t deserve to get a free lunch on top of it.

You might wonder how I can justify that statement when most students have very low incomes. Well, they are not rich because of their present income, but because of the income they will earn in future. Three years after completing their degree, a bachelor’s graduate will earn 51% more than someone with only secondary qualifications. Someone with a master’s degree will earn 74% more and a doctoral graduate 120% more. Yet it was the secondary graduate, working full time while the student was studying, that helped fund about 75% of their education. How can that possibly be fair?
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