Offering 0pen and Honest Professional Advice
Schliecher PIisa admitted his Pisa plans were viewed as mad by the OECD - so do many academics
Pasi Salsberg, Finish Educationalist refers to it a virus. Professor David Reynolds and Dylan Wiliam has criticised it.
I am not aware that Andreas Schliecher has explained what he admitted went wrong with the 2015 Pisa results.
Is Pisa Rigged? - Fobes Article