Time in the class and educational attainment: evidence from PISA

In the soul searching that has followed the release of the Leaving & Junior Certificate exams and particularly in the context of the maths results some commentators have pointed to the relatively low hours in class spent by Irish students. Does it actually matter? This paper shows that it does:

Do Differences in School's Instruction Time Explain International Achievement Gaps in Maths, Science and Language? Evidence from Developed and Developing Countries
Victor Lavy
There are large differences across countries in instructional time in schooling institutions. Can these differences explain some of the differences across countries in pupils' achievements in different subjects? What is the likely impact of changes in instructional time? While research in recent years provides convincing evidence about the effect of several inputs in the education production function, there is limited evidence on the effect of classroom instructional time. Such evidence is of policy relevance in many countries, and it became very concrete recently as President Barrack Obama announced the goal of extending the school week and year as a central objective in his proposed education reform for the US. In this paper, I estimate the effects of instructional time on students' academic achievement in math, science and language. I estimate linear and non-linear instructional time effects controlling for unobserved heterogeneity of both pupils and schools. The evidence from a sample of 15 year olds from over fifty countries that participated in PISA 2006 consistently shows that instructional time has a positive and significant effect on test scores. The effect is large relative to the standard deviation of the within pupil test score distribution. The OLS results are highly biased upward but the within student estimates are very similar across groups of developed and middle-income countries. However, the estimated effect of instructional time in the sample of developing countries is much lower than the effect size in the developed countries. Several checks for threats of identification support the causal interpretation of this evidence. I obtain very similar results when I use as an alternative data from primary and middle schools in Israel and a somewhat different identification strategy

Evidence on how the quality of professors matter

Applied economists have become enthusiatic users of natural experiments to generate exogenous variation in key independent variables although it has been argued that this approach has severe limitations: particular instruments may not identify parameters of interest (see Heckman passim). The paper below I think is quite an imaginative use of a "natural experiment" from a dark period in history to see how the quality of professors matter for their graduate students.

Quality Matters - the Expulsion of Professors and Ph.D. Student Outcomes in Nazi Germany
Fabian Waldinger

I investigate the effect of faculty quality on Ph.D. student outcomes. To address the endogeneity of faculty quality I use exogenous variation provided by the expulsion of mathematics professors in Nazi Germany. I find that faculty quality is a very important determinant of short and long run Ph.D. student outcomes. A one standard deviation increase in faculty quality increases the probability of publishing the dissertation in a top journal by 13 percentage points, the probability of becoming full professor by 10 percentage points, the probability of having positive lifetime citations by 16 percentage points, and the number of lifetime citations by 6.3.

Lazear on class size effects

The link below has a nice summry of Ed Lazear's work on class-size effects (h/t Alan Fernihough)
http://www.hoover.org/publications/digest/3476106.html
A more technical version is at:
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=194830

Class-size effects in PISA : further results

Further to my recent post, I show a somewhat detailed analysis above. The dependent variable is the students reading score which is an arbitrary function of class-size (i.e. in their English class, since this is data for Ireland) and of the teacher/pupil ratio in the school. In addition, I control linearly for the students sex, their age in months (they are all about 15), their birth order, their fathers education, school type (private/public) and a few measures of the home environment (like number of books). These controls don't actually make much difference.
So again we see a positive gradient with students in bigger classes doing better though it seems flatter than previously shown. The teacher/pupil ratio doesn't matter: using the absolute number of pupils gives the same result i.e. there are no economies or diseconomies of scale. Repeating the analysis for the maths score gives much the same results. The positive gradient is a puzzle though this is not the first time it has been found.

Teacher quality

Everybody knows that schools differ massively in their quality. This is not just - or even especially- an Irish phenomenon. However finding the elusive factors that determine what make schools good has proved both scientifially challenging and politically tricky. There is now a fairly substantial body of evidence showng that reducing class size is not that important, certainly once it is below a certain level. Nonetheless it continues to get a lot of air-time here partly because teachers' unions like it (no surprise there) and because it is intuitively appealing.
The emphasis elsewhere has shifted, the US' No Child Left Behind Act introduced by George W. Bush focused attention on school accountability. This idea has certainly not caught on here in Ireland where lack of accountability is effectively enshrined in law: data on school performance may not be published.
Some researchers in the US, notably Eric Hanushek of Stanford University, have emphasized the importance of teacher quality. In an interesting development, policy makers have got behind the idea of teacher quality, under the Race to the Top program, and have linked states' access to funds available through the stimulus package. Specifically, states are being asked to reform around four areas:

• Adopting standards and assessments that prepare students to succeed in college and the workplace and to compete in the global economy;
• Building data systems that measure student growth and success, and inform teachers and principals about how they can improve instruction;
• Recruiting, developing, rewarding, and retaining effective teachers and principals, especially where they are needed most; and
• Turning around our lowest-achieving schools.

The article below from the Atlantic Monthly has a very good overview of these developments. Given the huge potential returns to society from improving educational attainments at school level (see my recent posting, link below), one wonders what does it take for policy makers, the education sector and the community generally to finally get serious about improving our schools?

http://www.theatlantic.com/doc/print/201001/good-teaching

http://gearybehaviourcenter.blogspot.com/2010/02/high-cost-of-low-educational_12.html

The high cost of low educational performance in Ireland

Recently Mark blogged here about a new OECD report with the above title (minus "in Ireland" of course, you can download the report from the link below). The report was written by Eric Hanushek and Ludger Woessmann. Hanushek gave a talk here this week (at U.Kentucky) which I attended and covered much of the territory from a US angle. I recommend the report to anyone interested in education: its short but there is a lot of important materiel in it.
It is largely concerned with the macroeconomics gains from improving our human capital. It evaluates a number of scenarios and uses increases in PISA scores as the potential reforms. PISA is a measure of learning outcomes, in several domains (reading, science, mathematics) for a large number of countries including the OECD but many others. Looking at measures of educational attainment scores, Ireland is generally pretty close to the OECD average.
I thought I would pluck out some of the Irish numbers i.e. the simulated impact of improving PISA scores. The different PISA test scores have an average of 500 and a standard deviation of 100. They use a discount rate of 3%.
Scenario 1:
Increase PISA scores by 25 points (0.25 of a std. dev.):
The discounted increase in GDP (until 2090) for Ireland is $514 bn
Scenario 2:
Bring each country up to the level of Finland:
The discounted increase in GDP is $870bn
This would require increasing our PISA scores by almost 41 points.
Scenario 3:
Bring everyone up to a minimum of 400 PISA points i.e. eliminate the lower tail of the distribution in each country.
The discounted increase in GDP is $530bn

Of course there is uncertainty around these projections but it is clear that these are vast amounts of money which dwarf the sort of sums that are talked about in policy contexts- in the context of NAMA, for example. Educational reform is never easy for all sorts of reasons so increasing PISA scores is not straightforward. Nonetheless the question we need to ask ourselves then is: can we afford not to do something about this?



http://www.oecd.org/dataoecd/11/28/44417824.pdf

School "league tables"

Ferdinand Von Prondzynski generously invited me to contribute a piece to his University Blog and I write about the arguments for not keeping parents in the dark about their children's school as they are at present in Ireland, a policy that is surprisingly popular amongst educationalists here 'though not with parents (as if their opinion mattered).

http://universitydiary.wordpress.com/2009/12/01/better-by-leagues/