Examples herein relate to determining a number of defective bit lines in a memory region prior to applying a program or erase voltages. If a threshold number of bit lines that pass during a program or erase verify operation is used to determine if the program or erase operation passes or fails, the determined number of defective bit lines can be used to adjust the determined number of passes or fails. In some cases, examples described herein can avoid use of extra bit lines and look-up table circuitry to use in place of defective bit lines and save silicon space and cost associated with the use of extra bit-lines. In some examples, a starting magnitude of a program voltage signal can be determined by considering a number of defective bit lines.