requirements before entering the teaching profession. Regarding the former, to upgrade existing teachers’ skills and qualifications, teachers will need continuous support. This is needed to increase the efficiency of their instruction and to build their practical pedagogical and digital skills, which are critical domains for learning recovery and acceleration (World Bank et al. 2022b).

In the case of the EAP region, what is the _relative_ importance of these two challenges: the need to upgrade the skills of the existing _stock_ of teachers versus the importance of hiring more (and better preparing) the _flow_ of new teachers? Using a simulation described below, this paper tries to quantify the relative importance of the two.

# III. Simulation: Teacher stock and flow in primary education in East Asia and Pacific middle-income countries, 2021–2030

## A simple model to forecast the relative importance of the stock versus the flow of teachers

As mentioned above, there are already estimates of how many teachers will be needed in the future. These estimates are based on simulation models.<sup>5</sup> To our knowledge, in these modeling exercises, there has been less focus on the importance of the _existing_ stock of teachers. Our paper helps fill this gap in a simple and, we hope, intuitive way.

The model is based on several factors, such as: (i) the size of future cohorts of children (which are exogenous to the education sector); (ii) the proportion of those cohorts who will end up in school (for which we make assumptions about net enrollment rates); (iii) the pupil-to-teacher ratio (PTR, a policy variable); and (iv) teacher attrition (for which we use historical data where available).

We hope this paper will be a useful input for policy makers’ and development partners’ deliberations on how to improve teaching quality.

Box 1. Simulation model: Steps, assumptions, and robustness check

|**A. Seven steps **|
|---|
|Step1. Estimate totalpopulation in EAP MICs|
|•<br>Access World Population Prospects 2022 estimates for each country up to 2040 (https://population.un.org/wpp/)<br>•<br>Use the indicator “population by 1-year age groups and sex”|
|Step2. Estimateprimaryschool-agepopulation in EAP MICs|
|•<br>Confirm education system for each country using indicators “official entrance age to primary education (years)” and “theoretical duration<br>of primary education (years)” from World Bank EdStats (https://datatopics.worldbank.org/education/)<sup>6</sup><br>•<br>Estimate primary school-age populations using data retrieved from World Population Prospects 2022 data|
|Step3. Estimate student enrollment inprimaryschools in EAP MICs<br>•<br>Estimate student enrollment in primary schools<br>•<br>Use the indicator “total net enrollment rate, primary, both sexes (%)” from World Bank EdStats|
|Step4. Estimate teacherposition needsperpupil-to-teacher ratio(PTR)in EAP MICSs<br>•<br>Use the indicator “pupil-qualified teacher ratio in primary education (headcount basis)” to estimate the number of teachers needed for<br>primaryeducation|

5 For instance, see International Task Force on Teachers for Education 2030 2021, UIS 2009 or UIS and EFA-GMR 2014.

> 6 Original data source is UIS.

4