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[2452] PAGE is statistically wrong

The Parent Action Group for Education (PAGE) is a group known for its strong support for the teaching of science and mathematics in English in Malaysian public schools (the PPSMI policy). Its chairperson Noor Azimah Abdul Rahim argues the serial improvement seen throughout the years of PPSMI is a proof of success. They argue that that improvement is due to the policy.[1]

I am unconvinced that that is the case because such statistics is so raw in its presentation that it does not control for other factors.

How would we know if that improvement was not secular? Students’ achievements have been improving over the years even before PPSMI. It will be wrong to attribute all of those achievements to PPSMI. That factor as well as others should be removed before any reasonable conjecture could be made between PPSMI and achievements that the exams supposedly measured.

After that, how would we know what fraction of the improvement (or indeed even decline given that we only see net result) was due to PPSMI?

Even if all of those are accounted for, these improvements within the interested period are small enough that they are probably within the series’ standard error. In other words, the improvement could simply be some random variation with the mean essentially unchanged.

Consider the following graph I have pulled out from Noor Azimah and PAGE’s defense of PPSMI.

Take the science rural figures. The mean throughout the years is 90.6. The 68% confidence interval is between 88.9 and 92.3. Observe how many data points are within that band. The 95% confidence interval is between 87.2 and 94.1. Remember, this is before secular trend that has nothing to do with languages is taken out.

So, serial improvement as shown by PAGE through various graphs reproduced in Noor Azimah’s write-up does not really answer these questions.

To conclusive answer the questions, one has to compare two parallels, i.e. compare two series — one for PPSMI and another the status quo — concurrently. This will control for many things like grade inflation, secular improvement due to merely better education facility and access and the difficulties of the exam. After controlling all of these things, only then language will be the only factor being tested.

These two series do not exist side by side unfortunately.

The problem with Noor Azimah and PAGE’s argument is that they are comparing something that exists against something that does not and goes on to conclude that one that exists is better statistically. That is intellectual dishonesty.

The fact is there is no statistics to make the relevant comparison possible. Hence, there is no fact to make PAGE’s conclusion possible.

And, lest pro-PPSMI cheer, this is a double-edge sword. The statistics does not say anything about the alternative Malay-policy either.

That is the point however. The statistics does not say anything. PAGE however sees an elephant in the clouds.

Mohd Hafiz Noor Shams. Some rights reservedMohd Hafiz Noor Shams. Some rights reservedMohd Hafiz Noor Shams. Some rights reserved
[1] — GMP (Gabungan Mansuhkan PPSMI), led by PAS members is pushing the Government to stand firm on abolishing PPSMI (The teaching and learning of Science and Mathematics in English) yet again, and claiming that only 3% of pupils benefited from PPSMI.

Evidence to support the continuance or abolishment of PPSMI, should be based on the achievements in UPSR, PMR and SPM. That should be the benchmark. The test results of these three national examinations, proved to be very encouraging, clearly supporting the continuance of PPSMI while contradicting all statements that have been brought against PPSMI. [Noor Azimah Abdul Rahim. Pro-English group hits back: Don’t twist the facts for “political expediency”. Malaysia Chronicle. October 29 2011]