The HMIE findings, in Mr Donaldson's words, represent a "work in progress".
So, since the inspection report, like the curate's egg, is bound to be only good in parts, there will be plenty of pickings for opponents and supporters of the agreement, not least for those intent on wielding a big stick with which to beat the Scottish Executive in an election year.
The teachers' agreement was not meant to be an overnight sensation. It has certainly improved the industrial relations climate in Scotland's schools, and there should be no belittling of that achievement. It looks as if this could be the first decade for some years in which it will be possible to say that education tops the education agenda. Difficulties there may be, but they are uncluttered by deep-seated grievances over pay and conditions.
The conclusions reached by the HMIE investigation essentially mirror those last year by Audit Scotland and the Scottish Negotiating Committee for Teachers: we have come a long way, but there are many miles to go before we sleep. Rarely can the outcome of national bargaining have been subject to so much scrutiny, but it is fatuous in the extreme to assume there can be a direct causal link between the agreement and the number of Highers that pupils achieve. Other factors, such as the nature of learning and the social context of schooling, come into play.
The unions are right to point out that any attempt to assess the agreement on the basis of improved pupil attainment is suspect. On the other hand, perhaps they need to revisit their own mantra that improvements in conditions for teaching are a pre-requisite for improvements in conditions for learning.