[Alneyan]

The magic level varies from province to province, and adds +1 to all research abilities per Magic level. So, under Magic +3, all your mages have +3 to research. Likewise, Drain reduces magic research, by the same amount.

Even if you did not pick a Magic scale, some sites increase the Magic scale, creating a "pocket" of magic in your Dominion, or it may simply be an effect of Dominion spreading.