An independent evaluation, published by the Scottish Executive, says there has been "a sea change in the availability and delivery of careers development support".
Of almost 40,000 who used the service in 2002-03, an estimated 25,800 started a new job within nine months. Of these, 17,000 or 66 per cent felt the guidance influenced them.
The evaluation, by economic development consultants Segal Quince Wicksteed, noted "the value attached to careers support by a very high proportion of clients (and an increasing proportion of the public)".
It added: "The evaluation shows that these services have made a major impact on the career development of a large number of people, both in terms of finding suitable employment and training and, just as importantly, providing the support, skills and confidence to make informed career decisions."
The report says the impact of careers support has been sustained despite the upheaval after the establishment of Careers Scotland in 2002, "a major success for all those involved".
Christina Allon, director of Careers Scotland in the Scottish Enterprise area, acknowledged the challenge of delivering a new service for adults, which was backed by Executive funding of almost pound;9 million for "all-age guidance projects".
She said: "We've established the importance of career planning as a life skill and introduced a model to develop it. The 'career planning journey'
diagnoses a person's stage in the career planning process and gives them the tools they need to take the next step."
Mrs Allon said the organisation would continue to target key groups - young adults out of work, those facing redundancy and people who need to raise their skill levels.
The SQW report accepted that, even without support, many unemployed adults would find jobs or training anyway. But it found nonetheless that careers support influenced their career decisions for the better, and that it gave them more confidence to make career development decisions.
Careers guidance was also found to have worked in steering people away from a specific career path. "These are positive outcomes both for the economy (as participants have found jobs or are training for jobs which better reflect their strengths) and for them personally," SQW says. "This is true even when individuals avoid wasting time following inappropriate ideas."
The recent changes to Careers Scotland have seen it spruce up its advice centres, establish a website, introduce a national phoneline (0845 8 502 502) and devise the "career planning journey" to identify the support people require. The agency has also launched a redundancy advice service for small businesses.
Awareness of Careers Scotland appears to have grown as a result. The proportion of the public who had heard of the agency rose from 37 per cent to 76 per cent over the two years to April last year, although there had been an advertising campaign in this period.
And those who said they would find careers guidance very useful rose at the same time from 12 per cent to 21 per cent, just over a fifth of the adult population.