To gain insight into how pupils perform in relation to the understanding of historical time, we  developed a measuring instrument with questions for each stage, based on the model with the three stages of development. The instrument was administered in seven primary schools with 1457 pupils from grades 3 to 8.

Mean percentages of correct answers per grade for stage A, B and C

The analysis shows that the percentages of correct answers  increase through the grades and that pupils in higher grades  significantly outperform pupils in lower grades.

For all grades the results seem to indicate that there is room for improvement, especially in the lower grades where pupils hardly had any teaching on the understanding of historical  time. But in grades 7 and 8 as well, pupils can still grow in the stage of continued understanding of historical time.