The assessment of literacy and numeracy skills of students as they enter school for the first time is not yet established nation-wide in Australia. However, a large proportion of primary schools have chosen to assess their starting students on the Performance Indicators in Primary Schools-Baseline Assessment (PIPS-BLA). This series of three studies aimed to establish whether (a) items in the Reading and Mathematics scales of the PIPS-BLA function differently for Indigenous and non-Indigenous students; (b) easier items developed for both scales are able to target Indigenous low-scoring students more reliably; and (c) factors such as gender, age, geolocation and ESL status are related to high and low levels of performance. The samples consisted of Indigenous and non-Indigenous students from metropolitan, regional and remote areas in Western Australia starting school in the years 2007 to 2013. The Rasch model was used to examine the operation of items. Both scales showed very little differential item functioning; the new items improved the measures for low-scoring students only marginally; and ESL status predicted performance most strongly. Female students performed better than male students and regional and metropolitan students better than remote students. These findings support previous research. Some reasons for the lowest performances are discussed.