Does a tax adviser make fewer errors than you do yourself?

A tax adviser makes fewer calculation and input errors than you do. That is mainly due to software and online filing. Whether the content of your return is more often correct is less certain. In American research, returns by paid preparers actually had an adjustment on audit more often than self-prepared returns. And in the Netherlands you remain responsible for your return, even if someone else completes it.

About the research in this article: most studies on tax return help come from the United States, with additional research from Italy and Australia. Different rules and a different advisory market apply there than in the Netherlands. The patterns are useful, but the exact percentages cannot be transferred one to one.

In this article

1. Does an adviser make fewer maths errors than you do?
2. Is the content of your return more often correct if an adviser completes it?
3. Why do auditors sometimes find more at advisers?
4. Is that down to the adviser or the client?
5. Who is responsible if your adviser makes an error?
6. Do you get a penalty if your adviser makes an error?
7. How do you reduce the risk of errors when an adviser files your return?

Does an adviser make fewer maths errors than you do?

Yes, far fewer. Maths errors (mistakes in adding up, incorrectly copied amounts and missed lines) rarely occur in returns by a paid preparer. But most of that advantage comes from the software, not from the adviser.

The American tax authority IRS examined all income tax returns for 2010. Of the returns that people completed themselves by hand on paper, 37.0% contained a maths error. For returns by paid preparers, the figure was 1.3% (Langetieg, Payne & Vigil, IRS).

The difference lies mainly in how the return is completed. A preparer working by hand made a maths error in 18.0% of returns. With software and online filing, this fell to 0.6%. People who prepared their own return with software and filed it online came to 1.1% (IRS). The difference between doing it yourself and using an adviser is then small.

Mismatches with third-party data, such as wage statements and bank data, were also slightly less common for preparers than for people using software themselves. But those mismatches depended more on how complex the return was than on who prepared it (IRS). In the Netherlands, data such as wages, the WOZ property value, mortgage details and bank balances are already included in the pre-filled income tax return. An adviser must still check that data and add to it where needed (Dutch tax authority).

Is the content of your return more often correct if an adviser completes it?

Not automatically. In a sample of audited American returns for 2006 to 2009, 60% of returns by paid preparers had an error that changed the tax due or the refund. For self-prepared returns, the figure was 50% (GAO, 2014).

Those figures do not yet show that the adviser is the cause. People with a complex return seek help more often, and a complex return is more likely to contain errors. A recent study tries to separate these effects. The researchers used around 135,000 random IRS audits from 2006 to 2014. Using a statistical method, they separated the effect of the adviser from the effect of the type of client. Their estimate: a paid preparer increases underreported income by about 3,900 dollars per return (DeBacker et al., 2024).

In the same study, volunteers who help people on low incomes for free performed as well as people who completed their own return (DeBacker et al., 2024). Almost the entire difference lay in income from sole proprietorships and in overclaimed American tax credits for low-income workers. These are items the tax authority can hardly check against third-party data (Indiana University, 2024).

Small field tests also reveal errors. Staff of the American audit office GAO went undercover to have their return prepared by 19 randomly selected preparers. Only 2 of the 19 calculated the correct amount. In 12 of the 19 visits, cash income such as tips was not reported (GAO, 2014). The GAO itself warns that 19 visits are too few to draw general conclusions.

Why do auditors sometimes find more at advisers?

Because an adviser works in two directions. On items where the rule is clear, an adviser makes sure you get it right. On items where the rule leaves room, an adviser more often tests the limits. This already emerged from research into American audit data per line of the return (Klepper, Mazur & Nagin, 1991).

On wages and salaries, preparers improved compliance. On a grey-area item such as work-related expenses, they actually caused more deviations (Andreoni, Erard & Feinstein, 1998). It is precisely those grey-area items that leave room for creative accounting and a generous reading of the rules.

This matters for business owners, because much of their return consists of such items. Think of whether an expense is business-related, how you depreciate something or which part of a car or workspace is private. On those points, the choice of adviser helps determine how far your return goes.

Is that down to the adviser or the client?

Both. People who hire an adviser differ greatly from people who file their own return. Business owners, older people, people with higher incomes and people with a complex return seek help more often (Andreoni, Erard & Feinstein, 1998). So part of the extra adjustments comes from who walks through an adviser's door.

But that does not explain everything. A study of around 14,000 randomly audited American returns from 1979 took that choice into account. The use of a certified public accountant or lawyer remained associated with more deviations in the return (Erard, 1993). Income from one's own business, a farm or rental made both help and deviations more likely (Andreoni, Erard & Feinstein, 1998).

Italian research on 2.5 million sole proprietors shows the same double picture. How much a business owner underreported was linked to how much the other clients of the same adviser underreported. The researchers found two explanations. Business owners choose an adviser who matches their own attitude. And advisers pass knowledge on between clients (Battaglini et al., 2019). This is a working paper, not yet peer reviewed in a journal.

Who is responsible if your adviser makes an error?

You are. Under the law, anyone invited to file a return must complete and submit it clearly, definitely and without reservation (Article 8 AWR). The AWR (the Dutch General State Taxes Act) makes no exception for returns completed by an adviser.

The courts apply it the same way. In 2018, the Amsterdam Court of Appeal ruled that a company is itself responsible towards the tax authority for filing its return on time. This also applies if the company uses a professional representative for this (Amsterdam Court of Appeal, 2018). The penalty for late filing stood, even though the adviser had ignored requests to file the return.

You also pay any tax underpaid yourself. In a Supreme Court case from 2017, payroll tax returns filed through an accounting firm wrongly included a reduction. The Supreme Court only sent the penalties back to the court of appeal for a new ruling. The correction of the tax itself stood (Supreme Court, 2017). Whether you can recover the loss from your adviser is a matter between you and the adviser.

Do you get a penalty if your adviser makes an error?

Not if you could reasonably rely on your adviser. According to the Dutch Supreme Court, you do not have to study the tax rules yourself if you hire an adviser you could consider sufficiently expert, and whose care you had no reason to doubt (Supreme Court, 2017).

That reliance does have limits. What matters is whether the arrangement with the adviser was such that you could count on the return being correct. In the 2017 case, the company had itself indicated which employees the reduction applied to. That is why the court had to examine whether the firm should also have checked the conditions itself (Supreme Court, 2017). So if you supply incomplete or incorrect information, it is harder to hide behind the adviser.

The tax inspector can only impose a penalty for an offence (a penalty for tax underpaid through your own fault) for taxes levied by assessment, such as income tax, in the case of gross negligence or intent (Article 67e AWR). Under the penalty policy, that penalty is 25% for gross negligence and 50% for intent (BBBB, § 25). With an arguable position (an interpretation of the rules you could reasonably consider correct) or if you are not at fault at all, there is no penalty (BBBB, § 4).

How do you reduce the risk of errors when an adviser files your return?

By knowing what kind of adviser you want, and by continuing to read the return yourself. In an Australian survey of 2,040 randomly selected taxpayers, most people wanted an honest adviser with little risk and little fuss. A small group actually looked for a creative, aggressive adviser (Sakurai & Braithwaite, 2003).

The difficulty is that you can hardly see the difference from the outside. According to the same researchers, taxpayers could not properly distinguish a cautious adviser who saves within the rules from an aggressive one (Sakurai & Braithwaite, 2003). So ask explicitly how your adviser deals with borderline cases. These five questions help:

1. Which items in my return are a matter of interpretation?

   Most adjustments arise on those items, so that is where you want to know which choice was made and why.

2. Is this position arguable, and can you substantiate it?

   An arguable position prevents a penalty, even if the tax authority disagrees with it.

3. Which information do you need from me, and do you check it?

   If you supply incomplete information yourself, it is harder to rely on the adviser.

4. May I see the return before you file it?

   You remain responsible for what it says, so read it before it goes out.

5. How do you keep track of deadlines?

   Even if the adviser is late, you get the penalty for late filing.

Taken together, the research points one way. An adviser removes the careless errors from your return. How far your return goes on items that leave room depends on the adviser you choose and on the agreements you make. That decision is yours.

Sources

• Langetieg, P., Payne, M. & Vigil, M. Return Preparer Industry Analysis. In: IRS Research Bulletin, 2013 IRS Research Conference (published 2014). Internal Revenue Service. irs.gov
• U.S. Government Accountability Office (2014). Paid Tax Return Preparers: In a Limited Study, Preparers Made Significant Errors. GAO-14-467T, 8 April 2014. gao.gov
• DeBacker, J., Heim, B.T., Tran, A. & Yuskavage, A. (2024). Seeking Professional Help: How Paid Preparers Decrease Tax Compliance. National Tax Journal, 77(2), 229-261. doi.org/10.1086/728928
• Indiana University, O'Neill School of Public and Environmental Affairs (2024). Explanation of the research by Heim and Tran on paid tax preparers, 27 August 2024. oneill.indiana.edu
• Klepper, S., Mazur, M. & Nagin, D. (1991). Expert Intermediaries and Legal Compliance: The Case of Tax Preparers. Journal of Law and Economics, 34(1), 205-229. doi.org/10.1086/467224
• Andreoni, J., Erard, B. & Feinstein, J. (1998). Tax Compliance. Journal of Economic Literature, 36(2), 818-860. ideas.repec.org
• Erard, B. (1993). Taxation with representation: An analysis of the role of tax practitioners in tax compliance. Journal of Public Economics, 52(2), 163-197. doi.org/10.1016/0047-2727(93)90019-P
• Battaglini, M., Guiso, L., Lacava, C. & Patacchini, E. (2019). Tax Professionals: Tax-Evasion Facilitators or Information Hubs? NBER Working Paper 25745 (working paper, not peer reviewed). nber.org
• Algemene wet inzake rijksbelastingen (General State Taxes Act), Article 8 and Article 67e, in force from 1 October 2026. wetten.overheid.nl
• Amsterdam Court of Appeal, 4 September 2018, ECLI:NL:GHAMS:2018:3696. uitspraken.rechtspraak.nl
• Besluit Bestuurlijke Boeten Belastingdienst (tax penalty decree), § 4 and § 25, in force from 8 August 2026. wetten.overheid.nl
• Belastingdienst (Dutch tax authority). Data in the pre-filled return for intermediaries, accessed 14 October 2026. belastingdienst.nl
• Supreme Court of the Netherlands, 3 February 2017, ECLI:NL:HR:2017:127. uitspraken.rechtspraak.nl
• Sakurai, Y. & Braithwaite, V. (2003). Taxpayers' Perceptions of Practitioners: Finding One Who is Effective and Does the Right Thing? Journal of Business Ethics, 46(4), 375-387. doi.org/10.1023/A:1025641518700