The New Zealand School Enrolment System

Typically in New Zealand, children whose birthdays occur in the second half of the year (July onwards) start primary school as a new entrant for their first two terms (terms 3 and 4 of the school year) and move into Year 1 at the beginning of the following year.  By comparison, those with birthdays in first half of the year (the end of the previous school year through to the end of June) will enter a new entrant or year 1 class upon turning five and will complete their new entrant/year 1 experience all within just a 6-12 month period before moving to year 2. This presents inequalities for students with the oldest students receiving up to 12 months additional school learning compared to the youngest students (see diagram below). However, this practice is not consistent across schools, for example, some schools use the end of Term 1/start of Term 2 as the cut-off period. Whatever the cut-off is within a school, though, this continuous and rolling enrolment system presents inequities for students based purely on birthdate—the oldest students in any given year group may benefit from up to 12 months of additional school learning compared to the youngest students. 

Research Findings

While it might be tempting to think that students might “all catch up at some point”, research shows that this is often not the case—findings suggest that the effects of early schooling opportunities can be relatively large and long-lasting.

•Cliffordson and Gustafsson (2008) (Sweden): Both schooling and age generally increase performance, with the effect of schooling being considerably larger than the effect of age.

•Cahan and Cohen (1989) (Israel): The effect of an additional year of schooling is on average about twice as large as the effect of being a year older.

•Leuven et al. (2010) (The Netherlands): One additional month of early schooling closes the achievement gap between *disadvantaged and non-disadvantaged students by nearly 10%. *Disadvantaged’ students are defined as those whose parents have at most a degree from low-level vocational school.

•Ali & Menclova (2024) (New Zealand study): One additional month of early schooling increases the probability of achieving a top high school certificate by 6% and qualifying for university entrance by 5%.

Intrigued by this research and also driven by my own hunch that students who had additional time at school would be educationally advantaged, I examined mathematics Progressive Attainment Test (PAT) scores from a local primary school and found that 52% of the oldest students (those with birthdates in April, May and June) had the highest stanines (stanine 7, 8 or 9) compared to only 29% of the youngest students (those born in December through to March). Conversely, only 3.5% of the oldest learners had the lowest stanines (stanine 1, 2, or 3) compared to 8% of the youngest. 

The "Matthew Effect"

The inequities noted in the research and from the school achievement data I collected might be attributed to the “Matthew Effect”—a pattern in which those who begin with advantage accumulate more advantage over time and those who begin with disadvantage become more disadvantaged over time. Our eldest students in a given year, are not only more developmentally advanced than our youngest but they have also received the most schooling (up to 12 months more).  The result is ever-widening differences between the advantaged and disadvantaged.