Longitudinal development of number line estimation and mathematics performance in primary school children

Children’s ability to relate number to a continuous quantity
abstraction visualized as a number line is widely accepted to be
predictive of mathematics achievement. However, a debate has
emerged with respect to how children’s placements are distributed
on this number line across development. In the current study, different
models were applied to children’s longitudinal number
placement data to get more insight into the development of number
line representations in kindergarten and early primary school
years. In addition, longitudinal developmental relations between
number line placements and mathematical achievement, measured
with a national test of mathematics, were investigated using
cross-lagged panel modeling. A group of 442 children participated
in a 3-year longitudinal study (ages 5–8 years) in which they completed
a number-to-position task every 6 months. Individual
number line placements were fitted to various models, of which
a one-anchor power model provided the best fit for many of the
placements at a younger age (5 or 6 years) and a two-anchor power
model provided better fit for many of the children at an older age
(7 or 8 years). The number of children who made linear placements