The OECD has published *Tax Administration 2025: Comparative Information on OECD and other Advanced and Emerging Economies*, the thirteenth edition of its Tax Administration Series (TAS). Approved by the Committee on Fiscal Affairs on 27 October 2025, the report examines national-level tax administration across 58 advanced and emerging economies. Alongside its usual annual performance benchmarks for fiscal year 2023, this edition takes a deliberate ten-year perspective, comparing current data with the earliest International Survey on Revenue Administration (ISORA) results from 2014.
The findings are drawn from the 2024 ISORA survey, launched in September 2024 and completed by 164 jurisdictions worldwide. The 58 administrations featured correspond to the group supported by the OECD. Data from the Inventory of Tax Technology Initiatives (ITTI) supplements the ISORA figures at several points, and more than 80 jurisdiction-supplied examples of innovative practice are woven throughout the text. All underlying ISORA data tables are publicly available via the ISORA online data portal.
The rise of artificial intelligence
The report's most prominent theme is the speed at which artificial intelligence has entered mainstream tax administration. When the first ISORA survey was designed around 2015, AI attracted no dedicated question. First data covering its use appeared for fiscal year 2016, when 9% of administrations reported deploying it. By 2023 that figure had reached 69%, with a further 24% reporting active implementation programmes. The report estimates that roughly one-quarter of all jurisdiction examples submitted for inclusion are AI-related, spanning analytics, casework selection, taxpayer-facing services and the automation of high-volume routine tasks.
The trend cuts across all operational functions. Canada's Revenue Agency uses AI to validate user identities online, eliminating the ten-day wait for a physical access code; 60% of users now opt for the digital route. Korea's National Tax Service has built AI search and pre-fill features into Hometax, a platform serving 37 million users. China's State Taxation Administration has embedded AI into a hybrid "intelligent plus manual" interactive services model through which 97% of tax matters and 99% of filings are handled online. The broader picture is of administrations using AI to absorb workload growth without proportionate increases in staff.
Revenue collections
Tax administrations collected an average of 22% of GDP in net revenue in fiscal year 2023, up from 20.9% in 2014. More striking is the share of total government revenue: administrations now account on average for 63% of all government receipts, a rise of nearly 8 percentage points since 2014. Forty-four of the 58 administrations covered exceed 50% of government revenue, confirming that tax administrations have become the dominant revenue arm of the state in most jurisdictions. Revenue grew by an average of 9.7% between 2022 and 2023, a slowdown from the post-pandemic rebound rates of 17% recorded in 2020–21 but still substantial.
VAT is the single largest revenue type, accounting for 30% of net collections and serving as the primary tax for 47% of administrations. Personal income tax (PIT) follows at 26%, corporate income tax (CIT) at 19% and social security contributions at 10%.
Electronic filing and payment
E-filing has effectively become universal. Between 2014 and 2023, average e-filing rates rose by 23 percentage points for PIT (from 66% to 89%), 19 points for CIT (from 77% to 96%) and 18 points for VAT (from 81% to 99%). For a significant number of administrations, 100% e-filing is already the reality across all main tax types. E-payment rates have followed the same trajectory: 90% of payments by number and 93% by value were made electronically in 2023, up around 10 percentage points from 2018.
That progress should not obscure the residual scale of paper transactions. Among jurisdictions that provided data, more than 75 million returns, spanning PIT, CIT, employer withholding and VAT, were still filed on paper in 2023.
On-time filing and payment
Despite the gains in e-filing and pre-filling, average on-time filing rates have been broadly static over ten years. For PIT, the rate as a proportion of returns expected moved from 86.2% in 2014 to 86.8% in 2023; for CIT it fell from 79.9% to 77.1%; for VAT it edged down from 85.1% (2016) to 84.1%. Expressed as a proportion of returns actually received, rates are higher (90.6% for PIT, 85.4% for CIT, 89.0% for VAT in 2023), but the stagnation relative to e-filing progress is notable and points to structural rather than administrative causes.
On-time payment performance tells a similar story. Rates expressed as a percentage of payments due dipped during the pandemic and have largely recovered, but sit slightly below their 2014 levels across all four major tax types. The employer withholding (PAYE) regime stands apart: its median on-time payment rate of 96% is well above CIT and VAT at 92%, reflecting the compliance-by-design effect of withholding at source. PAYE regimes operate in 93% of jurisdictions; withholding accounted for 78.5% of PIT revenues in 2023 on the available data, though the report notes that a change in the underlying survey question reduced comparability for that year.
Pre-filled returns
Close to 90% of administrations now pre-fill PIT returns, stable since 2021 but up nearly 9 percentage points from 2018. The most common pre-populated data categories are taxpayer personal information (98% of pre-filling administrations), wages and salary (88%), pension income (82%), interest (58%) and dividends (56%). An increasing number of jurisdictions have moved to fully pre-filled returns, where the taxpayer either confirms or corrects. Several administrations are extending the concept beyond PIT to CIT, PAYE and VAT returns, aided by electronic invoicing systems. Denmark has implemented real-time validation that blocked more than one million changes per year, identifying a difference of nearly DKK 1.1 billion (approximately EUR 150 million) between initially rejected submissions and final assessments.
Registration and identity management
All 58 administrations offer multiple registration channels, and 98% allow online registration, a 35-percentage-point increase since 2014. Three-quarters of administrations report the existence of cross-government databases spanning population, business, property and motor-vehicle registers.
Digital identity is already pervasive: 98% of administrations require individuals to use an approved digital identity to access secure online services, and in two-thirds of cases the digital identity issued by the tax authority can also be used to access other government services. Multi-factor authentication is in place at 70% of administrations. A small number use facial recognition (17%) or fingerprint recognition (17%). The report notes that AI-enabled image and audio generators are creating new identity-theft risks that require sustained investment in anti-fraud controls.
Compliance management and enforcement
The report identifies a potentially significant shift in compliance behaviour over the decade. While audit adjustment rates have remained broadly stable since 2014, the additional tax raised through audit as a percentage of net revenue has fallen materially for PIT, CIT and VAT. The report suggests this may reflect effective upstream compliance programmes, improved taxpayer education and a deterrent effect from administrations holding greater data volumes. It is presented as a hypothesis rather than a firm conclusion, but it is consistent with the investment in data analytics documented throughout the report.
By 2023, 69% of administrations used big data and AI for analytical risk management purposes. Electronic invoicing mandates are expanding. Israel's Tax Authority implemented a prior-approval model for invoices above NIS 50,000 (a threshold falling to NIS 5,000 by 2028), identifying approximately NIS 30 billion of fraudulent invoices in 2024 and saving an estimated NIS 6 billion in VAT. Spain's VERI*FACTU project requires certified invoicing software and QR-code verification. France uses algorithms to detect businesses in financial difficulty before they accumulate unpayable tax debts.
Tax crime investigation responsibilities rest primarily with the tax administration in 43% of jurisdictions (direction and conduct combined) and in a further 26% conducted under the authority of another agency. The remainder sit entirely outside the tax administration.
Debt collection
Outstanding tax arrears at year-end 2023 stood at approximately EUR 2.7 trillion across the administrations covered, up from EUR 1.5 trillion in 2014 in absolute terms. However, expressed as a ratio to annual net revenue, average arrears have fallen by around 10% over the same period, reflecting faster growth in revenue collections. The report uses a Tax Debt Management Maturity Model self-assessment tool to benchmark collection function capabilities; results reveal a wide range of maturity levels across jurisdictions.
Dispute resolution
Between 2022 and 2023, the number of cases on hand at year-end moved in divergent directions across jurisdictions, with no clear aggregate trend. Around two-thirds of jurisdictions resolve the majority of internal reviews in favour of the administration. The report gives particular attention to dispute prevention, covering co-operative compliance frameworks, advance pricing agreements and mutual agreement procedures. Japan's co-operative compliance programme for large enterprises and Poland's digitalised tax ruling process are among the examples cited. The United Kingdom has introduced a strategic litigation pipeline to prioritise cases of wider legal significance.
Budget and workforce
Sixty percent of administrations report declining staff numbers in absolute terms. The average population and labour force per full-time equivalent has increased by around 15% between 2014 and 2023. Digital transformation is absorbing some of this pressure, but the workforce data points to structural strain.
The age profile compounds the challenge. On average, 28% of tax administration staff are aged 55 or older and face retirement within the coming decade. Between 2014 and 2023, the proportion of staff with less than five years of service rose by 7.4 percentage points. Administrations are investing in recruitment and knowledge transfer programmes, and the VITARA initiative (Virtual Training to Advance Revenue Administration) receives dedicated coverage in this chapter.
Salary costs remain the dominant operating expenditure item. The report includes a useful discussion of the limitations of the "cost of collection" ratio as a cross-jurisdiction efficiency comparator, noting that differences in administrative scope, social security responsibilities and accounting conventions can make direct comparisons misleading.
Taxpayer services
Contact volumes have shifted dramatically. Online contacts via taxpayer accounts exceeded 3 billion in 2023, triple the 2018 figure. In-person contacts fell by 56% since 2014. Telephone contacts remained relatively stable at around 300 million. Ninety-one percent of administrations formally measure taxpayer experience with online services. Several have deployed generative AI to process taxpayer feedback at scale: Canada's Revenue Agency used a generative AI tool to categorise over 90,000 user comments, identifying ten priority improvement areas and achieving a 158% increase in user success rates for registration and sign-in tasks.
The document text reproduced in the source is explicitly truncated after Chapters 1 to 5 and portions of the chapter introductions; the published report contains considerably more, including full data tables, box examples and Annexes A and B listing data tables and participating administrations respectively. Practitioners benchmarking a specific administration, interrogating trends in a single tax type or examining innovative practices in a particular function will need to consult the full report.
The underlying ISORA data is publicly available and updatable at isoradata.org. Supplementary technology data from the ITTI database is published in the companion report *Tax Administration Digitalisation and Digital Transformation Initiatives*.
Primary sources
- Tax Administration 2025: Comparative Information on OECD and other Advanced and Emerging Economies (OECD, 2025) — official publication page and download
- ISORA online data portal — underlying survey data tables
- Tax Administration Digitalisation and Digital Transformation Initiatives (OECD, 2025) — ITTI companion report
- Inventory of Tax Technology Initiatives — ITTI database
- OECD Forum on Tax Administration
- Designing a National Strategy against Tax Crime: Core Elements and Considerations (OECD, 2024)