You can find more information about the validation process that IDELA underwent on this site using the following links:

Measuring School Readiness Globally:

Measuring School Readiness Globally

Developing and Validating the International Development and Early Learning Assessment: https://idela-network.org/resource/developing-and-validating-idela/

Assessing the Construct Validity of IDELA: https://idela-network.org/resource/assessing-the-construct-validity-of-save-the-childrens-international-development-and-early-learning-assessment/