3/13/2000
1 .prn files contain domeain-checked data. The wrong values, if any, are replaced by null string. Since each field is dilimited by ",", run a search for two consecutive commas (",,") in a .prn file will lead to where wrong data values used to be in the data set.
2 .chk files contain only lines of records where the wrong values are replaced with null string
3 .rpt files contain only records where wrong values are not replaced by null. Instead, they are marked with an asterisk.