The box 1a total dividends included as income (generally would increase your tax).
Box 1b. Qualified Dividends - An amount entered into line 1b is qualified dividends and is subjected to the capital gains tax rate instead of ordinary income so it should reduce your tax as long as your ordinary income is in a higher tax rate than your capital gains tax rate for your income level.
Box 1a includes amounts entered in boxes 1b and 2e and it also includes the amount of the recipient's share of investment expenses that you report in box 6
Refer to the IRS Instructions for 1099-DIV
