Over-reliance on tests is undermining the education system, it says.
The claim is made by Brian Boyd, emeritus professor of education at Strathclyde University in Glasgow, in a research paper for the Jimmy Reid Foundation. He blames university entry requirements for the exams "treadmill" faced by students.
His report comes at a time of significant change in Scottish school education with the introduction of the Curriculum for Excellence (CfE). Part of the rationale for CfE was to reduce assessment for pupils and ensure they learn a broader range of skills, but many schools have proved resistant.
The new report, A Common Weal: Education, states: "Examinations dominate secondary schools. They influence the shape of the school day, they are the starting point of the timetable and ... they dictate how many subjects a pupil may study.
"They distort the curriculum; they narrow the focus of learning and, as the exam diet draws closer, deep learning becomes a luxury. The goal is to get through the syllabus and second-guess what the examination paper will contain. The stress is often palpable as the exams approach.
"If this case is accepted, it follows that the present national assessment programme, with its heavy emphasis on timed, pencil-and-paper exams, is no longer fit for purpose."
Instead, the report calls for a single qualification - which could be designed along the lines of the international baccalaureate.
It calls for an "exit exam" system, only in the last year of school. The report said this would "assess how well a pupil has learned and how well they are able to apply their learning in new and different contexts."
The report added: "These could be different exams for different purposes, taking into account the proposed destinations of the student." It describes universities as the "tail which wags the dog" - with qualifications remaining rigid along traditional subject boundaries to suit higher education.
"Exams, largely to serve the needs of universities and possibly employers, are subject-focused and so the curriculum has to follow suit," the report states. "Students can achieve success in Highers with the minimum of understanding of the defining characteristics of, say, physics, or mathematics, or history."
However, a spokeswoman for Universities Scotland, which represents university principals, said there had been significant reforms to university admissions in the past couple of years.
She said: "Positively engaging with CfE has meant adapting to suit the new kind of school-leaver and universities have moved to make greater use of contextual admissions. Both changes will bring about greater recognition of extra-curricular achievement and enhanced flexibility in the routes pupils can take to achieve their exams.
"However, a university degree is a significant undertaking and universities have a responsibility to ensure they are admitting students that have the ability to meet the academic demands that will be placed on them."
Overall, the report calls for the Scottish system to more closely follow the Finnish model, where children start formal learning at seven, where pupils are not streamed on the basis of ability and where formal examinations do not take place until they are aged 18. Finland recently came top of the international Programme for International Student Assessment (Pisa) ranking.
Last week, it emerged the Scottish Qualifications Authority has provided schools with only a single specimen paper for each National qualification.
Pupils are having to rely on relevant sections of previous exams, such as Standard Grade, to give them more examples of the likely questions.
The Scottish Parliament's education committee is looking at the rollout of the CfE and its associated exams. The Jimmy Reid Foundation is a left-wing think tank and advocacy group which was established in memory of the prominent trade unionist.