In a posting last week, I discussed the tools under existing law for curbing bad tax return preparers and suggested that these tools may not adequately address the problem. Too many returns are poorly done. Many taxpayers are victims, not only of incompetence, but fraud. The other victim is the government, which likely loses substantial tax revenue from those whose returns are poorly—or dishonestly—prepared.

But how should preparers be regulated? A distinction between those I think of as tax professionals and all other preparers may be a helpful starting point for answering this question.

I use the term “tax professionals” to refer to lawyers, CPAs, and enrolled agents. Attorneys and CPAs are licensed by their states, and solely on the basis of this accreditation may practice before the IRS at all levels. Attorneys can also represent taxpayers in the Tax Court and other federal courts. Enrolled agents are licensed by the IRS and can represent taxpayers at all levels in the IRS.

These professionals also prepare many returns, but they don’t need a license to do that work. Preparers, in fact, are not required to have any education, training, or license. Does the training of tax professionals make them better at preparing returns? Sadly, the answer may be: Not necessarily.

Enrolled agents may provide important lessons for those who advocate licensing all tax return preparers.

The usual route to becoming an enrolled agent is passing an examination created and administered by the IRS, but former IRS employees may be enrolled without an examination after at least five years of IRS experience in positions requiring them to apply and interpret tax laws. An enrolled agent must annually complete at least 16 hours (often 24 hours) of continuing education. The IRS’ Office of Professional Responsibility may suspend or disbar an enrolled agent (or attorney or CPA) who fails to adhere to a detailed code of conduct (Circular 230). A national association of enrolled agents has more than 40,000 members.

At first glance, this sounds like an ideal solution. Train budding tax preparers, make them pass an exam, require them to keep up with the always-changing law, and give the IRS the authority to disbar the bad apples. It may not be feasible to require all preparers to pass an examination as rigorous as the enrolled agents’ test, but some system of examinations, continuing education, and ongoing oversight should improve the overall quality of return preparation.

A recent study by Sagit Leviner and Kyle Richison suggests caution about this conclusion. It reviewed nearly 3,500 returns claiming the earned income credit, all of which had been audited by the IRS. It found CPAs and attorneys did the best job, although the IRS still made changes on nearly half of their returns. Taxpayers who prepared their own returns did almost as well. The most error-prone category of all preparers? Enrolled agents!!

This study does not purport to be comprehensive. There may be reasons other than incompetence why enrolled agents performed so poorly. They may, for example, get disproportionately more returns of taxpayers with more difficult returns (e.g., self-employed persons).

At a minimum, however, the study suggests that testing and education alone are likely not a panacea. Even after all preparers are licensed, the IRS will have to vigorously apply the penalty and injunction rules against incompetent and dishonest preparers. For that, the IRS will need sufficient resources. If we are going to persist in our maddeningly complex tax system (well illustrated by the earned income credit), multiple efforts will be needed to make sure those on the front lines of preparing returns know what they are doing.