The Republican lawmakers have sold the corporate portion of their tax cuts with the claim that it is actually about helping workers. Their argument is that the corporate tax cut will lead to so much growth that the increase in wages will actually be considerably larger than the tax cut itself. The GOP’s story is that lower corporate taxes inevitably mean more investment, which means higher wages for more workers, as well as increased imports and greater productivity.

The vast majority of economists have questioned this basic logic, because in the past, investment has not been highly responsive to after-tax rates of profit. But that didn’t stop the Republican-controlled Congress from passing the tax bill. And now, in an effort to build public support for the corporate tax cut, several major corporations have been announcing bonuses and pay raises for workers.

AT&T announced that it would give a one-time bonus of $1,000 to 200,000 workers. Its rival Comcast also promised a $1,000 bonus for 100,000 workers. Fifth Third Bancorp promised a $1,000 bonus for 13,500 employees, while raising its minimum wage to $15 an hour. Wells Fargo said it would raise its minimum wage to $15 an hour, too. Boeing announced a $300 million fund to be spent on training workers, upgrading facilities and matching workers’ charitable contributions.

While the employees getting these increases will undoubtedly be pleased, there are a few caveats that must be kept in mind.

First, many of these announcements refer to one-time bonuses, not permanent pay hikes. This is not what the GOP promised. The corporate tax cuts were made permanent on the grounds that companies needed the expectation of higher future after-tax profits in order to justify greater investment today. If the economy is following the course predicted by the Republicans, all these pay increases should be permanent, too.

The second caveat is that some of the increases may have little to do with the tax cut. They can be attributed instead to the tightening labor market, along with higher minimum wage laws. This is especially true of Wells Fargo, which is based in California. The state has already passed into law a $15 minimum wage, which is scheduled to be fully phased in by 2022.

Wells Fargo will be getting there a bit more quickly if it adopts its $15 minimum in 2018. It will also be applying that hike in parts of the country where the federal minimum wage of $7.25 an hour still sets the standard, but even in these other areas, a tightening labor market is putting upward pressure on wages. Last summer, Target announced that it would get to a minimum wage of $15 an hour by 2020. That announcement had no obvious connection to any expectation of a corporate tax cut.

Third, but perhaps most significantly, these pay hikes are not especially large relative to the size of the corporate tax cut. Take the example of AT&T: In 2016, the company reported operating income, net of interest, of $19.4 billion. It paid $6.5 billion in taxes, which means an effective tax rate of 33.5 percent.

If it had instead paid the 21 percent tax rate in the new bill, AT&T’s savings would be $2.4 billion. The promised bonus for 200,000 employees comes to $200 million, or less than one-tenth the size of the tax cut. This is very much in line with the expectations of tax bill critics, who predicted that the overwhelming majority of the money that corporations now get to keep will end up as higher profits paid out to shareholders, not as permanently higher wages for workers.

But the real question is not the immediate split between wages and payouts to shareholders. The Republican story of tax cut blessings rests on a great surge in investment. We should begin to know if that is going to happen very soon. After all, companies were obviously following the tax cut debate over the last two months and presumably began to make plans as to what they would do if the bill passed.

So if there is going to be the huge upsurge in investment predicted by tax cut supporters, it should be showing up in the data on orders for capital goods almost immediately. And it should be a very large upturn, not just the normal increase to be expected in an economy that has been strengthening for the last eight years.

Until we get those data, we have little basis to judge whether the tax cut will deliver the economic growth and pay increases the Republicans said would happen. This display of corporate beneficence to workers and communities is nice, but it has to be understood as part of a public relations campaign. It tells us nothing about whether the tax cut will ultimately deliver to workers the gains promised by its proponents.