What does Missing (Other) mean?

The CPES dataset uses the following missing data codes:
Missing (Other) generally is used for numeric questions for which interviewers were instructed to enter a special code for responses that did not fall within a valid code range, for example, "97" for "DOES NOT APPLY" in response to a frequency question that allowed for a two-digit response. In the public release dataset all such responses have been changed to "-7". For more information, please consult Data Processing Note, which includes a table that summarizes questions for which this missing data code applies.