The FORMAT statement is classed as non-executable and can, in principle, go almost anywhere in the program unit. A FORMAT statement can, of course, be continued so its maximum length is 20 lines. The same FORMAT statement can be used by more than one data transfer statement and, unless it contains character constant descriptors, used for both input and output. Since it is very easy to make a mistake in matching the items in a data transfer list with the edit descriptors in the format specification, it makes sense to put the FORMAT statement as close as possible to the READ and WRITE statements which use it.