The tidal wave of interest in formative assessment has been a mixed blessing. No one doubts its crucial role in providing a foundation for the other two strands of Assessment is for Learning (AifL): personal learning planning (assessment is learning) and local moderation (assessment of learning).
But the attention given to assessment for learning has made promoting the other strands difficult and many have come to think that AifL is just about formative assessment.
Nothing could be further from the truth. Assessment for learning may be the bedrock for a coherent system of assessment, but that cannot be sustained by formative assessment alone, especially if it is construed as essentially a collection of teaching strategies with no sustaining rationale or purpose.
Assessment for learning has helped to restate the purpose of classroom assessment as supporting learning, not just measuring it, as happened in the 1990s when national testing covered a narrow range of attainment and probably served to focus effort on to the skills pupils needed to pass tests.
Formative assessment, on the other hand, tells us that learners learn by their own efforts, that they should be given the opportunity and the skills to assess their own progress and that, to achieve this, teachers need to find new ways of working with learners.
In essence, assessment for learning is about using the communication that passes between teachers, pupils and parents to stimulate and support effective learning opportunities.
Rather than being told what they are to do, pupils come to an understanding of what they will learn by doing it and how they will recognise evidence of their own success as they work.
Rather than waiting to the end before they assess a piece of learning, teachers can gather evidence of their pupils' learning through dialogue designed to inform and support it as it happens.
Rather than having assessment done to them, pupils are able to take a much more active role in evaluating their own progress.
A culture of classroom assessment based on thoughtful interaction between teachers and pupils is at its most effective when pupils have learned how to plan their own learning (assessment as learning) and teachers and pupils have a shared understanding of the standard they are working towards (assessment of learning).
Unless sustainable connections are made across the three strands of AifL, the underlying conflicts between the summative and formative purposes of assessment may never be resolved and we may never find a tenable way of using assessment to both support learning and report on progress.
So, while many see formative assessment as very important, assessment as and of learning have no less a role to play.
What of the current state of formative assessment in Scotland, then? More than half of Scotland's schools have now been directly involved in AifL, the majority exploring aspects of assessment for learning.
Evaluations of work so far have been positive: there have been relatively few difficulties in implementation; there is evidence of dramatic improvement in pupils' learning skills and a shift from teacher-centred pedagogy.
The challenges to sustained dissemination are perceived to be continuing tensions between formative and summative assessments, between covering content and fostering deep understanding, between teaching responsibilities and having time to reflect on current practice, between the demands of different national initiatives.
Many early enthusiasts worked in primary schools but more and more secondary teachers are now recognising that assessment for learning has something to offer across subject boundaries and even in the upper school where the pressures of summative assessment are at their strongest.
Some, like Bannockburn High in Stirling, have been involved from the start and are now using their experience of formative assessment to inform their work in personal learning planning.
Others are using local moderation approaches to agree common standards for judging pupils' learning. As a result of activity like this in many schools, we may soon be in a position to appreciate that these aspects of the AifL programme have much to offer in the search for improved learning experiences for all.
Eric Young works with Learning Unlimited, providing consultancy support to the AifL programmewww.ltscotland.org.ukassess