Pisa tests 15-year-old students in reading, maths and science. More than 400,000 students from 57 countries and regions took part in 2006 when Hong Kong students came second in science and third in maths and reading. This year, 72 countries and regions will participate. The test takes place from next month until May.
On Monday, the HKCISA appealed to schools to take part after not enough signed up for the test, saying they were too busy dealing with education reforms. The bureau brushed aside the centre's concern the next day, calling it a "false alarm" and saying there was "no question of Hong Kong not participating".
But Professor Ho said the message was wrong. The government failed to "understand the actual situation" and sent out "a wrong message" to the public by misjudging the sampling requirement.
"It was very irresponsible to make such a comment," she said.
Professor Ho also expressed a concern that schools might be pressured by the administration to take part in the test.
"If Hong Kong is lacking students and falls out of Pisa's international rankings, the government will have to take up the responsibility," Professor Ho warned.
She said she had been working on Pisa for 10 years and did not want to see the hard work jeopardised. This year's test was particularly significant because it was the first time Macau, Hong Kong, Shanghai and Singapore would be compared internationally at the same time.
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