The Educational Institute of Scotland will launch its election manifesto on Monday, setting out demands for more professional autonomy and a more positive climate of "talking up" education if standards are to be improved.
The institute kicked off its campaign on Tuesday with a call to the Secretary of State to review the Government's approach on target-setting. Ronnie Smith, the union's general secretary, said a review must be an early priority for the new First Minister.
The Scottish Office dismissed this as "old ground", but the EIS has been buoyed by independent research it commissioned from Linda Croxford of the Centre for Educational Sociology at Edinburgh University. Dr Croxford's highly critical conclusion is that HMI-driven targets are the product of "statistical illiteracy".
Her report states: "Although many parents may be aware of the inadequacy of league tables based on raw examination results, we might suggest that league tables based on the current target-setting methodology could be more harmful because of their spurious impression of accuracy."
Speaking at EIS headquarters on Tuesday, Dr Croxford agreed that value-added results, seen as a superior method for checking on the performance of schools, were not "the be-all and end-all" either. The crucial factors were pupils' attainment before they entered school as well as at different stages of schooling, information which did not exist on a Scotland-wide basis at present.
Dr Croxford does not favour publishing performance tables "unless and until there is confidence in the methodology" and warned there had been no research to back the target-setting initiative.
Mr Smith endorsed the report's findings which showed that deriving targets from pupils' entitlement to free school meals was "woefully inadequate". He said the measure was driven through the Education Minister's action group on standards, of which he was a member, despite "strong reservations" signalled by himself and the leading parents' representative.
Dr Croxford said deprivation factors explained only half of the difference in free meal entitlement between schools. There were significant regional differences and random fluctuations, since some parents who were entitled to apply for free meals did not.
"If other measures of school intake were included, such as prior attainment or parental qualifications, the rank ordering of schools would be different, and different school comparisons would be made," Dr Croxford said.
Dr Croxford and Mr Smith called for targets to be negotiated with individual pupils, rather than aggregated across schools.
A Scottish Office spokesperson said: "The action group on standards, on which the EIS was represented, accepted free school meal entitlement as the best indicator available. Provisional targets were derived from using FMEs, but the schools were able to vary them according to local circumstances to set final targets.
"It is regrettable that the EIS is choosing to go over old ground. What is important now is that schools have set achievable and stretching targets, and are working towards raising standards."
But Mr Smith countered: "The HMI defence that free meals is the best indicator we have got rather gives the game away.
"It is a meaningless number-crunching exercise which will not contribute one iota to raising pupil achievement, and we are concerned that credence is being given to it by people who ought to know better."
The EIS received firm backing from the Scottish Parent Teacher Council. Alison Kirby, the council's convener, called for "an end to education by numbers and a return to school-based initiatives to raise attainment".