An initial draft of the survey of young people's attitudes to life, partly sponsored by the Scottish Executive, showed that only 62 per cent expected to leave school with Standard grades.
In 2003, the first year of the biennial survey carried out by Mori Scotland, 87 per cent had hopes of at least one qualification. At Higher, hopes have also slipped, from 72 per cent in 2003 to 61 per cent this year.
When the final survey was published, no reference was made to the findings. The only comment made about education was about expectations of going to college or university.
"The figures relating to educational expectations were withdrawn because of a technical problem," Patrick McMenamin, head of youth intelligence and international affairs at YouthLink, said. "It was not an attempt to whitewash the issue. We found we couldn't make comparisons with the previous findings and so we removed them to avoid confusion."
In an apparent contradiction of the decrease in anticipated school qualifications, those who said they hoped to go on to further or higher education stood at 70 per cent, a slight drop from 71 per cent in the previous survey in 2003.
Girls (76 per cent), non-white young people (81 per cent), those from two-parent households (70 per cent) and those whose mothers work (69 per cent) were all significantly more confident of attending university.
The survey, which YouthLink hopes will build a robust picture of young people's views and attitudes, questioned 3,178 11-25s throughout Scotland.
The questionnaire was comprehensive, looking at attitudes and expectations, including their educational expectations.
The survey also featured career and job expectations, showing the proportion of 11-16s who agreed they had good job prospects in the future fell from 59 per cent in 2003 to 52 per cent in 2005.
Among 17-25s, however, there was greater optimism, with the proportion of those who felt that they have good job prospects climbing from 54 per cent in 2003 to 61 per cent in 2005.
While listening to music remains the most popular spare-time activity for 11-16s, the results indicate that the "keep active" message may be getting through. The proportion of those who said they were most likely to take part in sports, games or fitness activities increased from 45 per cent in 2003 to 54 per cent this year.