April 2019

Tax Administration Diagnostic Assessment Tool (TADAT) Field Guide

This guidebook provides trained assessors with a structured, standardised methodology, the Tax Administration Diagnostic Assessment Tool (TADAT), with which to undertake an objective performance assessment of a country’s tax administration system.


TADAT is a global tool that can be used by any country to assess the relative strengths and weaknesses of its tax administration system and its level of maturity in the context of international good practice. 

TADAT assessments do not examine administration of all national taxes but rather focuses on the administration of the major direct and indirect taxes critical to central/federal government revenues. 

TADAT assessments are particularly helpful in:  

  • identifying the relative strengths and weaknesses in tax administration; 
  • facilitating a shared view on the condition of the tax administration among all stakeholders; 
  • setting the reform agenda, including reform objectives, priorities, initiatives, and implementation sequencing; 
  • facilitating management and coordination of internal or external support for reforms and achieving faster and more efficient implementation; and 
  • monitoring and evaluating reform progress by way of repeat assessments at two to three-year intervals.