No abstract

Administrations in public education can do little besides struggle to balance the number of needed and available teachers. Conventional student-teacher ratios perpetuate trends and are unfit for policy making. Besides lacking a suitable alternative, the Portuguese government was concerned that declining birth rates might make tenured teachers redundant over time. Their hiring policies became gradually more conservative and less transparent, and grievances escalated. An SD model provided rigorous estimates for the number of public grade and secondary teachers needed in each Portuguese school district, per teaching group (science, English, etc.). The model combined a structure of three goal-seeking aging chain arrays. Its results were used to quantify and allocate tenured teacher vacancies in 2015. The model showed that redundancy concerns were unfounded and hiring for all vacancies was justifiable in the future. These results might have been difficult to anticipate by human decision makers because of the delays involved.