It depends.
- Were you eligible for a tax credit last year that didn't apply this year
- Did you have another source of income this year which wasn't there last year?
- Did you change your job or withholdings?
- Did you have higher deductions last year than this year?
I would recommend reviewing items you had input into your return last year to ensure you are not missing a deduction that you had reported in the past but may not have entered into your return this year.