The phrase "to raise the floor" means to increase the minimum level or standard of something. It indicates an improvement or enhancement in a particular area. Full definition
If these two options for the hand and arm placement are too much for your hips, simply raise the floor by placing a stack of books under you hands. (womenshealthandfitness.com.au)
While struggling to raise the floor in K - 12 education, we've failed to lift the ceiling. (educationnext.org)
But we must be wary of policies that raise the floor while ignoring the ceiling. (educationnext.org)