A balanced classification problem has classes with approximately equal numbers of observations. Checking class counts before modeling helps determine whether accuracy gives a useful performance picture. section 4.2.1
Price classification targets
A median-price target produces 24,472 cases below or at the threshold and 24,423 above it, making the binary target balanced. A five-class percentile target is also broadly balanced, with class counts ranging from 8,384 to 10,809. section 4.2.1
