The president of the General Council of Administrative Managers of Spain, Fernando Jesús Santiago Ollero, warns of a growing phenomenon: the combined use of the Tax Agency’s draft return and artificial intelligence tools as a supposed guarantee that the tax return is correctly prepared.
“We are beginning to see something that concerns us particularly: taxpayers telling us they don’t need a review because they have run their income through an AI and it told them it’s fine. And that is exactly the problem,” says Santiago. “A tax return is not just a calculation. It is an interpretation of a real person’s life. And that, today, neither the draft nor any AI can do. AI works with what you feed it… and the problem in tax returns is precisely what is missing.
The General Council reminds of a key issue that each year causes errors: all self-employed workers are required to file an income tax return, regardless of their income. Likewise, recipients of the Minimum Living Income (IMV) must file. And those receiving unemployment benefits do not have to file merely by virtue of receiving them.
What the Draft (and AI) Do Not See
The association notes that the draft is a proposal based on available data, but not a complete snapshot of the taxpayer’s situation.
“There is an essential part of the income that is never in the data the tax authorities handle: the part only the taxpayer themselves knows. And that’s where errors occur,” explains Santiago. “And, on occasions, data reported by other companies are incorrect. They must always be checked.”
Among the aspects not automatically incorporated are numerous deductible expenses that do not appear on any information return, such as union dues or professional association fees, legal defense costs, or many housing-related expenses—repairs, improvements, insurance, property management or depreciation—as well as the business expenses themselves.
In the area of leases, issues such as actual rental periods or the property’s condition over the year are not correctly reflected, factors that are decisive for the final result.
“Technology can add, but it can’t ask questions. And in taxes, what’s important isn’t only what is there, but also what is missing,” says the president of the Administrative Managers.
There are also significant limitations in applying family minimums and disability considerations, where complex personal circumstances—dependents, shared custody, specific requirements—require individualized analysis.
Add to this are difficulties in correctly determining capital gains and losses, where items such as the cost basis or the costs associated with buying or selling are not always properly reflected.
“We encounter every year taxpayers who think their return is correct because the system doesn’t tell them otherwise. But the system isn’t designed to detect what it doesn’t know,” warns the president. He also cautions about common errors arising from third-party data, such as employers, and about omitting foreign income, which isn’t always automatically incorporated.
“Every change can be an opportunity… or an error if not applied correctly,” sums up Santiago, who delivers a clear message: “It’s not about whether you get a refund or owe. It’s about whether it’s done correctly. Because the real danger isn’t paying more. The real danger is believing everything is correct when no one has interpreted your situation. We always advise the same: review the draft in detail and, in case of doubt, consult a professional.” And ends the president of the Administrative Managers by stating that “today, more than ever, filing your tax return without guidance is a gamble… and many times you lose without realizing it.”
