Students from poor families perform poorly in mock exams for universities and have a much higher failure rate than those from non-CSSA families.
The results are based on a mock Diploma for Secondary Education hosted by Youth New World between October and December last year.
A total of 5,000 students, including 3,000 from families receiving Comprehensive Social Security Assistance, took the exam, which comprised 13 papers in four subjects.
The fail rate among the CSSA students was 5 to 10 percent higher than non-CSSA students.
But in English the fail rate was 38 percent, or 16 percentage points higher than non-CSSA students. In maths it was 40 percent or 12 points higher.
Youth New World vice chairman Tang Wing-yiu said the main reason why students from CSSA families fared poorly in English is because they lack the language environment since most of them attend Chinese- language schools.
Tang urged the government to provide these students with additional support or to provide alternative development paths if their exam results are not good enough for university entrance.
He said these students lack financial support from their families and will face a bleak future without a clear career plan.
Since each primary school in Hong Kong receives HK$500,000 to promote career planning for students, he suggested schools use the money to educate students to better understand themselves and to plan for their futures.