National guidelines should be drawn up on how complaints about police forces are recorded, the watchdog has said.
The Police Complaints Commissioner for Scotland said he was concerned the system does not reveal the number of people who complained about an issue.
John McNeill said this means the police have no way of knowing how significant a single issue has become.
He has written to the Association of Chief Police Officers in Scotland chief Pat Shearer about his concerns.
Mr McNeill called on Acpos to develop comprehensive, national guidance on the issue.
He said: "It's all about consistency.
"The public needs to be confident that, no matter where they make a complaint, it will be recorded and reported in a consistent way across all of Scotland's police forces.
"I am looking to Acpos to take the lead in actively developing national guidance."
Scotland's police complaints commissioner provides independent scrutiny of the way the police handle non-criminal complaints from the public.