We sought feedback and advice from external experts on the WET gap on the appropriateness and robustness of our new estimation method based on a multi-stage regression approach. Poisson pseudo maximum likelihood (PPML) regression better fits the data and enables us to use a richer dataset, improving the reliability of the estimates. They have supported our revised reliability rating of medium with a score of 18.
Figure 3: Reliability rating scale from very low to very high WET gap