Central to New Zealand National Standards is the concept of overall teacher judgements (OTJs). This paper examines the concepts of OTJs and standards through international literature and experiences of a sample of New Zealand teachers in 2010. Standards contain expectations—what is, what could be and what might be desirable— implicit degrees of performance. Teacher capacity to judge current and future performance is important. With multiple opportunities to gather pertinent information, teachers are best placed to make valid (unequivocal) judgements on student achievement when they have shared understandings of standards. Because standards are comprised of multiple criteria, not all of which are evident in samples of student achievement, teacher understanding of standards develops through professional conversations and moderation processes. In 2010 New Zealand teachers had mixed (equivocal) understandings of National Standards, applied them in different ways and had minimal experience of moderation processes.