Title page 1

Contents 7

Preface 4

Foreword 5

Acknowledgements 6

Reader's guide 12

Abbreviations and acronyms 17

Executive summary 20

1. Introduction 22

Structure of the 2025 edition 24

References 25

2. Responsibilities and revenue collections 26

Introduction 27

Responsibilities of tax administrations 27

Revenue collections 31

References 35

3. Registration and identification 36

Introduction 37

Levels of registration 37

Registration channels 37

Integration with other parts of government 38

Identity management 39

References 42

Note 42

4. Assessment 43

Introduction 44

Use of e-channels for filing and paying 44

Pre-filled returns 47

On-time return filing 50

On-time payment 53

Refunds and credits 57

References 58

5. Services 59

Introduction 60

Understanding and meeting taxpayer preferences 60

Educational and support initiatives 69

Collaborative services 71

Inclusive administration 75

References 77

6. Compliance management 78

Introduction 79

Compliance risk management 79

Performance in addressing non-compliance 94

References 99

7. Collection 100

Introduction 101

Features of a debt collection function 101

Performance in collecting outstanding debt 104

References 109

8. Disputes 111

Introduction 112

Dispute resolution review mechanisms 112

Dispute prevention 117

References 120

Note 121

9. Budget and workforce 122

Introduction 123

Budget 123

Workforce 130

References 144

Annex A. Overview of the ISORA data tables 146

Annex B. Participating tax administrations 152

Tables 9

Table 2.1. Revenue types for which the tax administration has responsibility, 2023 27

Table 2.2. Role of administrations in tax crime investigations, 2022 29

Table 2.3. Change in total net revenue collections, 2018-23 31

Table 2.4. Average net revenue collected as a percentage of GDP and total government revenue, 2014 and 2023 34

Table 2.5. Average percentage of personal income tax withholding, 2018-23 35

Table 3.1. Availability of registration channels for taxpayers, 2022 38

Table 3.2. Common cross government databases, 2024 38

Table 3.3. Use of digital identities, 2024 39

Table 3.4. Digital identity authentication, 2024 39

Table 4.1. Average e-filing rates by tax type, 2018-23 44

Table 4.2. Average e-filing rates by tax type, 2014 and 2023 45

Table 4.3. Average e-payment rates by number and value of payments, 2018-23 45

Table 4.4. Pre-filling of personal income tax returns, 2018-23 47

Table 4.5. Categories of third-party income information used to pre-fill personal income tax returns or assessments, 2023 47

Table 4.6. Categories of tax deductible expenses used to pre-fill personal income tax returns or assessments, 2023 48

Table 4.7. Average on-time filing rates by tax type, 2018-23 51

Table 4.8. Average on-time filing rates by tax type, 2014 and 2023 51

Table 4.9. Average on-time payment rates by tax type, 2018-23 54

Table 4.10. Average on-time payment rates by tax type, 2014 and 2023 55

Table 4.11. Treatment of VAT refunds, 2023 57

Table 5.1. Measuring taxpayer experience in using online services, 2024 60

Table 5.2. Service demand by channel, 2014-23 62

Table 5.3. Online services offered by tax administrations by tax type, 2024 63

Table 5.4. Online services with automated responses by tax type, 2024 63

Table 5.5. Use of virtual assistants, artificial intelligence and application programming interfaces, 2018-23 65

Table 5.6. Use of AI during interactions with taxpayers (other than virtual assistants), 2024 66

Table 5.7. Tax related services as part of a wider government service approach by tax type, 2024 72

Table 5.8. Development of Application Programming Interfaces, 2024 73

Table 6.1. Electronic invoicing and devices that register transactions, 2023 81

Table 6.2. Data governance, 2024 82

Table 6.3. Use of big data and artificial intelligence for analytical purposes, 2024 84

Table 6.4. Use of data science tools, artificial intelligence and robotic process automation, 2018-23 85

Table 6.5. Importance of large taxpayer offices / programmes (LTO/P), 2023 89

Table 6.6. Large taxpayer offices / programmes: Existence and functions carried out, 2023 90

Table 6.7. High net wealth individuals programmes: Existence and functions carried out, 2022 90

Table 6.8. Electronic compliance checks, 2023 94

Table 6.9. Audit adjustment rates and additional assessments raised, 2018-23 95

Table 6.10. Audit adjustments rates, 2014 95

Table 6.11. Average of additional assessments raised through audit as percentage of tax collected by tax type, 2014 and 2023 98

Table 6.12. Evolution of tax crime investigation cases referred for prosecution between 2018 and 2022 98

Table 7.1. Average arrears ratios, 2018-23 105

Table 7.2. Average arrears ratios, 2014 and 2023 105

Table 7.3. Evolution of average ratio of year-end arrears to net revenue collected by tax type between 2018 and 2023 108

Table 8.1. Taxpayer's rights and obligations 112

Table 8.2. Dispute resolution: Available review mechanisms, 2023 112

Table 8.3. Dispute resolution: Change in number of cases initiated during the year, 2018-23 113

Table 8.4. Dispute resolution: Change in number of cases on hand at fiscal year-end, 2018-23 114

Table 8.5. Average number of internal review cases initiated per 1 000 active PIT and CIT taxpayers, 2018-23 116

Table 8.6. Existence of formal co-operative compliance approaches for different taxpayer segments, 2023 119

Table 9.1. Changes in operating expenditures, 2018-23 123

Table 9.2. Average salary and ICT cost as percentage of operating expenditure, 2014 and 2023 128

Table 9.3. Average cost of collection ratio, 2014 to 2023 128

Table 9.4. Evolution of number of full-time equivalents, 2014-23 131

Table 9.5. Average ratios of population and labour force per full time equivalents (FTE), 2014 to 2023 131

Table 9.6. Average staff usage by function, 2014 and 2023 132

Table 9.7. Average age profiles of tax administration staff, 2014 and 2023 134

Table 9.8. Average length of service of tax administration staff, 2014 and 2023 135

Table 9.9. Average share of female staff and female executives, 2014 and 23 136

Table 9.10. Average attrition and hire rates, 2014 and 2023 138

Figures 8

Figure 2.1. Net revenue collected as a percentage of gross domestic product, 2023 32

Figure 2.2. Net revenue collected as a percentage of total government revenue, 2023 32

Figure 2.3. Average net revenue collections by major revenue type, 2023 33

Figure 3.1. Registration of active personal income taxpayers as percentage of population, 2023 37

Figure 4.1. Range in on-time filing performance across jurisdictions by major tax type, 2023 52

Figure 4.2. Range in on-time filing performance across major tax types by jurisdiction, 2023 53

Figure 4.3. Range in on-time payment performance across jurisdictions by major tax type, 2023 56

Figure 4.4. Range in on-time payment performance across major tax types by jurisdiction, 2023 56

Figure 6.1. Compliance risk management process 79

Figure 6.2. Percentage of revenue administered through large taxpayer offices/programmes, 2023 89

Figure 6.3. Audit adjustment rates, 2023 95

Figure 6.4. Additional assessments raised through audit as percentage of tax collections, 2023 96

Figure 6.5. Range of additional assessments raised through audit as percentage of tax collected by tax type, 2023 97

Figure 6.6. Additional assessments raised from audits undertaken by large taxpayer offices/programmes as a percentage of additional assessments raised from all audits, 2023 97

Figure 7.1. Results of the Tax Debt Management Maturity Model self-assessments 103

Figure 7.2. Total year-end arrears as a percentage of total net revenue (for administrations with a ratio above 50%), 2023 106

Figure 7.3. Total year-end arrears as a percentage of total net revenue (for administrations with a ratio below 50%), 2023 106

Figure 7.4. Total year-end collectible arrears as percentage of total year-end arrears, 2023 107

Figure 7.5. Movement of total arrears between 2022 and 2023 108

Figure 7.6. Range of year-end arrears to net revenue collected by tax type, 2023 109

Figure 8.1. Internal review procedures: Change between 2022 and 2023 in the number of cases on hand at fiscal year-end 114

Figure 8.2. Independent review by external bodies: Change between 2022 and 2023 in the number of cases on hand at fiscal year-end 115

Figure 8.3. Number of internal review cases initiated per 1 000 active PIT and CIT taxpayers, 2023 115

Figure 8.4. Percentage of cases resolved in favour of the administration, 2023 116

Figure 9.1. Salary cost as a percentage of total operating expenditure, 2023 124

Figure 9.2. Staff usage by function, 2023 132

Figure 9.3. Average age profiles of tax administration staff, 2023 133

Figure 9.4. Staff older than 54 years: Movement between 2018 and 2023 134

Figure 9.5. Average length of service vs. average age profile, 2023 135

Figure 9.6. Percentage of female staff - total female staff vs. female executives, 2023 136

Figure 9.7. Percentage of female recruits, 2023 137

Figure 9.8. Attrition and hire rates, 2023 138

Boxes 10

Box 1.1. Denmark - Strategic framework for digital transformation 23

Box 2.1. Finland - Credit register 27

Box 2.2. Tax crime investigations 29

Box 3.1. Examples - Identity management 40

Box 4.1. Examples - Electronic filing 46

Box 4.2. Examples - Pre-filling developments 48

Box 4.3. Examples - Spotting errors 49

Box 4.4. Netherlands - Tax-splitter on Value Added Tax 53

Box 4.5. China (People's Republic of) - Innovations in data-driven approaches to review of Value Added Tax credit refunds 57

Box 5.1. Examples - Understanding and meeting taxpayer preferences 61

Box 5.2. Examples - Enhancing self-service through online channels 64

Box 5.3. Examples - Artificial intelligence 66

Box 5.4. Examples - Educational and support initiatives 69

Box 5.5. Examples - Reducing burdens by joining-up 72

Box 5.6. Examples - APIs 73

Box 5.7. Examples - Inclusion 75

Box 6.1. Examples - Digitising processes 81

Box 6.2. Data governance 82

Box 6.3. Examples - Bringing data together 84

Box 6.4. Examples - Use of advanced analytics techniques for risk management 86

Box 6.5. Chile - International metrics: risk zones 88

Box 6.6. France - Using algorithms to detect businesses in difficulty 91

Box 6.7. Examples - Behavioural insights and nudges 92

Box 6.8. Latvia - Taxpayer ratings update 93

Box 7.1. Examples - Improving debt collection 101

Box 7.2. Spain - Risk analysis strategies for recovery investigation 104

Box 8.1. United Kingdom - Strategic litigation pipeline 113

Box 8.2. Resolving international tax disputes 116

Box 8.3. Poland - Digitalising tax ruling processes 118

Box 8.4. Japan - Co-operative compliance for large enterprises 119

Box 9.1. Examples - Initiatives to improve efficiency and productivity 124

Box 9.2. Difficulties and challenges in using the "cost of collection" ratio as an indicator of efficiency and/or effectiveness 129

Box 9.3. Brazil - Human Resources planning 130

Box 9.4. Examples - Recruiting and retaining staff 139

Box 9.5. The VITARA initiative 140

Box 9.6. Examples - Supporting staff 142

Annex Tables 10

Table A A.1. Overview of the ISORA data tables: Review tables 146

Table A A.2. Overview of the ISORA data tables: Derived tables 149

Table A A.3. Overview of the ISORA data tables: Periodic tables 150

Table A B.1. Overview of tax administrations included in this report 152