Liberal studies textbooks that focus on teaching current affairs require too many revisions because of the fast-moving nature of the content, the consumer watchdog says.
Publishers should exclude such topics from their books instead of using updates as an excuse to make parents spend on new volumes, the Consumer Council advised.
"Current affairs are changing too quickly and it is not right to include them in liberal studies textbooks, which are different from newspapers and magazines," Michael Hui King-man, chairman of the council's publicity and community relations committee, said yesterday.
Liberal studies became compulsory for older secondary pupils in 2009 to develop skills in critical thinking.
The subject has six modules: personal development and interpersonal relationships; Hong Kong today; modern China; globalisation; energy, technology and the environment; and public health. It also covers topics such as the rule of law and Hongkongers' identity.
But the Education Bureau does not include books on the subject in its recommended textbook list. This frees publishers from regulations that bar revisions within five years of the launch of the current edition, essentially allowing for frequent updates to the textbooks.
"If incorporating current affairs into a textbook can help educate a concept, it certainly deserves merit," council chief executive Gilly Wong Fung-han said.
"But using the need to update current affairs as an excuse to make parents buy new textbooks at higher costs is not right."
The council conducted an annual survey of 15 textbooks including music, Chinese history, Putonghua and liberal studies.
Overall, five volumes were judged "necessary" for revision because of outdated content, and a further nine were deemed "somewhat necessary".
Among the three liberal studies textbooks, two of them, published by Ling Kee Publishing, were assessed to be "somewhat necessary" for revision.
The third, by Pearson Longman, was in need of a "reprint with amendments".
The council received 11 complaints about textbooks and exercise books last year and 10 complaints the year before.
Professional Teachers' Union president Fung Wai-wah said books on liberal studies were trickier to publish, given that the subject was relatively new and many of its topics required discussion about the latest issues in current affairs.
"Topics such as environmental issues change rapidly," Fung said. "Publishers should think about how to publish a textbook without the facts getting outdated within just a year.
"For fast-changing aspects such as government data or policies, the publisher may want to consider referring to external sources such as government websites to avoid obsolete figures in print."
Fung said it would be ideal to include liberal studies textbooks on the bureau's list so that revisions could be regulated. The bureau said it did not recommend schools use textbooks as the primary learning and teaching resource for liberal studies.