When you run a job with the FREQUENCIES command, you get back something called a frequency table . This is simply a table that tells you how frequently each of the responses occurs. Generally, the table will provide you with the file name , the variable, and the details of the frequency command, which include: value, actual frequency, percent, valid percent, cumulative percent, missing, and totals.
If you find codes in the frequency table that are not supposed to occur in the data, you need to go back and correct or at least check them.