In a controlled experiment what is the experimental group compared to?

In a control experiment the experimental group is the one which is subjected to be affected by the variables used in the experiment. The changes occurring after treatment yields the outcome of the experiment. But the control group is the one which is not treated with any variable. It is kept as a standard for comparsion with the experimental group.

The controlled group, (the experiment group is there to compare your results to the control group)