It's simple. They took less tax out, so don't expect as much back

The Treasury Department rolled out new data explain to taxpayers that their 2018 refunds were smaller because they received most of their tax cut in the form of bigger paychecks last year.

“Most people are seeing the benefits of the tax cut in larger paychecks throughout the year, instead of tax refunds that are the result of people overpaying the government,” a Treasury Department spokeswoman said. “Smaller refunds mean that people are withholding appropriately based on their tax liability, which is positive news for taxpayers.”

The Treasury Department said average refunds during the first two weeks of tax-filing season were down 8.7 percent from the same period a year ago to $1,949. The new law cut taxes for about 80 percent of filers, though the amounts vary widely.

via The Wall Street Journal> As Refunds Shrink, Treasury Dept. Reminds Workers of Bigger Paychecks