A baseline which is set to 0 is automated, meaning it's set at the bottom of the object. Any other value than 0 is the y-coordinate on the screen, so if you set it to 1, it will be at the top of the screen.
Edit: My guess is that you think that a positive or negative number moves the baseline up or down, which is not how it works.
Edit: My guess is that you think that a positive or negative number moves the baseline up or down, which is not how it works.