Children in all public primary schools in Queensland, Australia have weekly music lessons designed to develop key musical concepts such as reading, writing, singing and playing simple music notation. Their understanding of basic musical concepts is developed through a blend of kinaesthetic, visual and auditory experiences. In keeping with the pedagogical principles outlined by the Hungarian composer, Zoltan Kodaly, early musical experiences are based in singing well-known children's chants - usually restricted to notes of the pentatonic scale. In order to determine the extent to which primary school children's musical understandings developed in response to these carefully structured developmental learning experiences, the Queensland Primary Music Curriculum was examined to yield a set of over 70 indicators of musical understanding in the areas of rhythm, melody and part-work,the essential skills for choral singing. Data were collected from more than 400 children's attempts at elicited musical performances. Quantitative data analysis procedures derived from the Rasch model for measurement were used to establish the sequence of children's mastery of key musical concepts. Results suggested that while the music curriculum did reflect the general development of musical concepts, the grade allocation for a few concepts needed to be revised. Subsequently, children's performances over several years were also analysed to track the musical achievements of students over time. The empirical evidence confirmed that children's musical development was enhanced by school learning and that indicators can be used to identify both outstanding and atypical development of musical understanding. It was concluded that modest adjustments to the music curriculum might enhance children's learning opportunities in music.