Charts: OECD Education at a Glance

by Enrico on October 29, 2008

in Experiments

Inspired by some recent government interventions on the Italian public school and the consequent large development of protests all around the country I have designed few charts to see if I can better understand the issue from the data and communicate some results.

Background

I have used the data from the Organization for Economic Co-operation and Development (OECD), which is often referred to as one of the main trusted authority for whatever concerns the education systems of a country. More precisely the data comes from the OECD report: “Education at a Glance“.
At the origin of the protest there is the reduction of the number of main teachers per class from 3 to 1, with a consequent reduction of the public personnel. The government says that having less teachers will not influence the quality of the studies and that quite a lot of public money will be saved. The protesters believe that the opposite is true and that the savings should not come from these cuts.
The goal of these charts is not to provide a solution to the debate, rather it is a very small and focused view on the problem. I just tried to find some hints on two related questions that came to my mind:

  • How efficiently does the Italian system spend its money?
  • Is proportion of students to teachers the cause of poor performance?

How efficiently does the Italian system spend its money?

The first chart replies to the first question. At least partially. The chart is a scatter plot of the OECD data on efficiency of school systems based on the following data:

Scientific performance: called PISA (Programme for International Student Assessment) and defined as “an international study conducted by the OECD which measures how well young adults, at age 15 and therefore approaching the end of compulsory schooling, are prepared to meet the challenges of today’s knowledge societies.” It is supposed to be a good indication of how well our schools do.
Expenditure per Student: It is defined as the equivalent US dollars expended per student.


chart1_s.png

I have drawn two lines to divide the space into 4 quadrants with respect to where Italy is placed. Of these quadrants I have highlighted the bottom right because it represents all countries who can perform better in terms of the PISA index and spend less. In other words all the countries in the quadrant not only are able to spend less but they also use this money more efficiently because they produce better students.
The sad truth is that my lovable country performs very bad. Greece and Portugal are valid companions but at least they spend less.
In oder to be sure that these results are not affected by the economic level of countries, I have also produced a second chart where the expenditure is normalized with respect to GDP (gross domestic product).

chart2_s.png

Unfortunately the result is even worse: Greece and Portugal perform worse but almost all the other countries are better. From the chart we can also see (in the bottom right) that Finland performs exceptionally well and that New Zealand, Netherlands and Australia performs very well too but spending less money.

Is proportion of students to teachers the cause of poor performance?

Since at the center of the debate there is the question of whether more or less teachers affect the quality of an education system, I created a bar chart comparing the ratio of students to teachers for the countries shown in the scatter plot.
Here are two bar charts, one for primary school and one for secondary school. Again I have highlighted Italy in the chart to make the comparison with it easy.

barchart1_s.png


barchart2_s.png

As you can see Italy has one of the lowest ratios both in primary and secondary school, meaning that there are quite a few students for each teacher or, in other word, that teachers are not very overloaded compared to other countries. The comparison with other countries is quite interesting. Finland, Netherlands and New Zealand (Australia is missing in the data) which are very efficient, as we have seen in the scatter plots above, have quite higher values compared to Italy. Can we say then that at the root of the poor Italian performance there is the number of teachers? Or can we say that a small number of students per teacher is necessary to produce a school of high quality? I don’t know … but at least the graphics instill some doubts.

Technical Notes

The charts have all been done with Excel. After all it is always the best and most readily available tool. There is always a bit of a hassle in doing certain things, especially the defaults are crazy (like strong dark backgrounds), but in the end it works great.
I have used the XY Chart Labeller to reduce label overlaps on the bar charts. This is also a bit cranky but in the end it does its job well.
The annotations on the charts have been done with the graphic tools in Excel and externally within SnagIt, which I use to screencapture the charts. Yes I’ve used screen capture! I know I could use VBScript stuff or similar things to save the charts into images but it’s always a kind of pain and less flexible than just press PrintScrn and edit the image.

Disclaimer

With these charts I don’t pretend to demonstrate anything, it’s more an interesting exercise for me to create data graphics and to show how easily we can reason about data that pertains to facts related to our social life.
The charts might show and evident bias towards judging the government interventions appropriate, but this is not my intent. Rather I would be very curious to see other charts that better clarify the issue and show with data and graphics arguments opposite to mine.

Final Reflection

In order to build these charts I have invested very very few time (I invested a lot more time to write this post though!). I was able in a few clicks to clarify to myself some things on an issue which is quite hot during these days in my home country and which I dare about. The same thing might be done by millions of citizens if only instructed appropriately. And that would mean having a population of informed people, able to ground their protests on hard data and to communicate their arguments with the vividness of well done data graphics.
Unfortunately this is very far to come. Simple techniques like these are never used by politicians or protesters, they prefer to use thousands and thousands of words in place of few well done charts. It’s a pity for us and it’s a pity for them.

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