Psychologists have declared campus police officers an overwhelming success, despite widespread concerns before they appeared in schools.
Staff, parents and pupils now agree that onsite police are important in making schools safe places, while the campus officers believe they have curbed truancy, fighting and smoking.
The evaluation was carried out by North Lanarkshire Council's psychological service, which stressed that the idea was not entirely popular before it was introduced in August 2007.
Teachers and trade unions had concerns about potentially criminalising children and compromising "some of the more sensitive pastoral and community issues". Parents feared police were arriving in schools because young people were out of control or teaching staff lacked authority. Headteachers, while "overwhelmingly supportive", wanted reassurance that they remained the main authority on discipline; campus police were not there to replace the school discipline system.
The survey, however, finds that staff, parents and pupils at the three schools involved - Wishaw's Clyde Valley High, Coatbridge High, and St Andrew's High in Coatbridge - all judge the scheme to be a success.
Staff generally deemed the campus police officer a "positive and valued addition", while the majority of pupils respected them and valued their "more friendly and relaxed approach". Parents "respected and valued" the role. All campus police were involved in the parent council and parent evenings, and had established "good working relations" with parents.
"The campus police officers saw their role within the school as stopping potential conflict between pupils through their presence," the report states.
"Through this preventative approach they felt they were able to curb truancy (in the school and in the local community), prevent smoking in and around the school, prevent shoplifting, vandalism, and litter-dropping within the community, prevent any potential fights arising, and ensure the safety of pupils.
"They also felt that by discussing any concerns pupils may have - for example, drinking or alcohol issues, drugs, anti-social behaviour - they could inform, influence and encourage responsible behaviour."
Staff, pupils and parents have similar views to police about what the role should involve: "building positive relationships between the police and community; preventing behavioural issues, for example, smoking, fighting, bullying; dealing with behavioural issues; educating and informing young people; organising trips and clubs; and ensuring the safety of the school, pupils and staff."
Teaching unions are generally supportive after having agreed a "campus police protocol", under-lining, among other things, that campus police answer to headteachers.
It also requires that officers "minimise the wearing of restraint and deterrent equipment within the school building and its grounds", stressing that "such equipment will remain securely held within the school and accessible only to the officer concerned".
One member of staff said the role of campus police had "evolved" and fitted into school life, despite the initial misgivings.
There was "unanimous" support for continuing the scheme when funding ends in March 2010. North Lanarkshire Council contributes pound;97,000 a year, funding two of the three posts, the other being paid for by Strathclyde Police.