To balance the scales means to make things fair or equal. It implies giving proper weight or consideration to different sides or parties involved in a situation. Full definition
Glad to be doing my part in balancing the scales of good news / bad news a bit. (whenthegirlsrule.com)
Under nature the slightest difference of structure or constitution may well turn the nicely balance scale in the struggle for life and so be preserved. (scientificamerican.com)
The challenge here is to balance scale with quality and precision. (entrepreneur.com)