VAT Introduction and Tax Mobilization in the Gulf: Synthetic Control and Event-Study Evidence

For centuries, governments have relied on a few reliable sources of income to keep their societies running. In many parts of the world, this money comes from selling oil or other natural resources. But when the price of those resources drops, or when the world changes, countries that depend on them can find their budgets in trouble. To fix this, economists have long argued that nations should build a broader safety net by collecting taxes directly from the daily spending of their citizens. One of the most powerful tools for this is a tax on goods and services, known as a value-added tax. Unlike a simple sales tax that is only collected once at the register, this tax is collected at every step of production, from the factory floor to the final sale, making it harder to hide and easier to collect. The big question for policymakers has always been whether introducing such a tax actually brings in the money they need, or if it simply causes people to stop buying things, or if it forces the government to cut back on other taxes to make up the difference.

In the Gulf region, a group of wealthy nations known for their vast oil reserves faced this exact dilemma. Between 2018 and 2021, four of these countries—Saudi Arabia, the United Arab Emirates, Bahrain, and Oman—decided to introduce a value-added tax for the first time. Before this, their governments collected almost no money from general consumption; their budgets were almost entirely funded by oil. What made this experiment unique was not just that they started from scratch, but that two of them, Saudi Arabia and Bahrain, later decided to raise their tax rates significantly. This created a rare opportunity for researchers to watch, in real time, how a tax behaves when it is first introduced and then when it is made more expensive. A researcher at King Faisal University, Mohammed Alomair, decided to study this event to see if the theory held up in practice. He wanted to know if the tax actually filled the government's coffers, if it replaced other sources of income, and if raising the rate simply brought in more money or if it made the system less efficient.

To answer these questions, the researcher used a method that acts like a time machine for economics. He gathered data from 163 different countries over a period of twenty-four years to build a picture of what would have happened in the Gulf nations if they had never introduced the tax. By comparing the actual numbers from the Gulf countries against a carefully constructed "synthetic" version of those same countries—created by averaging the economic patterns of similar nations that did not adopt the tax—he could isolate the true effect of the policy. He also looked at how the tax revenue changed year by year, checking to see if the rise in tax money was a genuine new source of income or just a shift from one pocket to another.

The results showed that the introduction of the tax was a clear success in terms of raising money. In the first year the tax was active, the amount of money collected from goods and services jumped by about 1.1 percent of the country's total economic output. By the third year, this figure had grown to roughly three percent. This was a significant boost, especially for nations that had previously collected almost nothing from this source. Crucially, the study found that this new money did not come at the expense of other taxes. The government did not have to lower taxes on income or trade to make the value-added tax work; instead, the total amount of tax revenue grew by the same amount as the new tax alone. This confirmed that the tax was truly adding new wealth to the state's budget rather than just rearranging existing funds.

However, the story became more complicated when the tax rates were raised. In Saudi Arabia, the government tripled the tax rate from five percent to fifteen percent. While this did bring in more money, the increase was not as large as the rate hike would suggest. For every percentage point the rate went up, the revenue did not rise proportionally; instead, the system became less efficient at collecting the full theoretical amount. The study found that the efficiency of collecting the tax dropped significantly, suggesting that as the rate got higher, people and businesses found more ways to avoid it, or the tax base shrank. In contrast, Bahrain doubled its rate from five percent to ten percent, and in this case, the efficiency remained high. The revenue grew almost in direct proportion to the rate increase. This difference suggests that there is a limit to how high a tax rate can go before it starts to lose its power, and that limit might be lower than some policymakers hope.

The research also looked at the broader picture by examining twenty-nine different countries that had introduced similar taxes over the last two decades. It found that the quality of a country's institutions played a major role in how much money the tax generated. Nations with stronger governance, better rules, and more effective administration were able to collect significantly more revenue than those with weaker systems. This implies that the success of a tax depends not just on the rate itself, but on the trust and capability of the government collecting it. The Gulf nations, despite being new to this type of tax, performed very well compared to the global average, largely because they built strong administrative systems before launching the tax.

Ultimately, the study offers a clear lesson for resource-rich countries trying to diversify their income. Introducing a broad, simple tax on consumption can quickly generate a substantial amount of new revenue without hurting other parts of the economy. However, the relationship between the tax rate and the money collected is not a straight line. Raising the rate too high can backfire, causing the system to become less efficient and yielding less money than expected. The most effective path forward appears to be maintaining a broad base with a moderate rate, supported by strong governance, rather than simply trying to squeeze more money out of the system by increasing the percentage. For the Gulf nations, this experience suggests they have successfully built a new pillar of their economy, but they must be careful not to push that pillar too hard.