Patricia Atkinson, head of Holy Trinity Episcopal primary in Stirling, maintains that pupils who think about what they are learning are able to make sound judgments to help further progress. They write comments like "this is something that could be improved or something that is very good".
Mrs Atkinson says: "Their assessments tended to be very close to the teacher's own assessment. When the children look into themselves it's much better than giving a mark such as eight or nine out of 10."
Her study in her previous Stirling school won first prize in the Scottish Council for Research in Education practitioner awards three years ago, although the findings were only released this week.
Only a minority of parents protested about pupils judging their own work and most backed their children's enthusiasm for the new methods. HMI has praised the effects on learning.
As ministers consider scrapping national tests and placing more emphasis on assessment of real classroom learning, Mrs Atkinson argues in a SCRE paper that self-marking and peer marking should be at the core of any new system if children are to be motivated to improve their learning.
Pupils in her present school draw up their own personal learning plans from the youngest ages.
Like others, she believes too much time and effort has gone into national testing but accepts the need for more formal assessment to ensure standards across schools.
In her study - designed to ask pupils and parents what they thought of 5-14 assessment - she found that pupils appreciate the value of assessment when they understand the purpose of each activity, what is going to be assessed and why.
"Pupils felt that responsibility for self-assessment and evaluation was useful even though it might be hard. They particularly liked the feeling of doing well when they had found something difficult," the former primary adviser states.
But a few parents were completely at odds. "Some parents were unsure of self-assessment and some were very uncomfortable with the idea of written peer assessment. This was not what the children thought," Mrs Atkinson said.
"My long-term experience is that when pupils mark, or even better, evaluate work for themselves, it benefits both teacher and child. It gives the teacher time for more detailed analysis of children's progress or problems, or for generally more useful preparation for future lessons in other subjects."
She adds: "Marking at the time, or immediately after finishing, is known to be beneficial to learning but many teachers find this too difficult to do in class, so mark after work."
Not one child during the study year commented negatively about another child's work.
"Assessment 5-14: What do pupils and parents think?" is published as Spotlight 87 by the SCRE Centre at Glasgow University.