Comps and voids are the two ways an item leaves a check without being paid for, and the difference between them matters more than most restaurants treat it.
A void removes something before it was made — wrong button, changed mind, ordered twice. Nothing was consumed and nothing was lost except the entry.
A comp removes something that was made. The food exists, the cost was incurred, and somebody decided not to charge for it.
Systems that lump them together make it impossible to tell a typing correction from a give-away, which is exactly the distinction worth seeing.
Why they need watching
Not because you assume the worst of your staff. Because these are the two transactions that remove revenue with a single tap and leave no physical trace, and a number nobody looks at is an invitation regardless of who is looking at it.
Most comping is legitimate: a dish sent back, a long wait, a regular's birthday, a mistake made good. That is a cost of doing business and it buys goodwill worth more than the food.
The problem is that legitimate and illegitimate comps look identical in a total. Only the pattern separates them.
What to look at
By staff member, per shift, as a percentage of their sales. Not in aggregate. One server at four per cent among a team at one per cent is a conversation, and it may well have an innocent answer — they work the section with the slow kitchen pass. You will not know until you ask.
By reason code. Which means having reason codes and requiring one. "Kitchen error", "long wait", "guest dissatisfied", "manager discretion". Without them you have a number and no story.
By time. Comps clustered at the end of a shift, or on the quietest night when a manager is not in, are a different shape from comps spread through service.
Voids after sending. A void on an item that was already fired is a comp wearing a void's name, and some systems allow it. Ask how yours behaves.
The controls that matter
Require a manager approval above a threshold. Small amounts by the server, anything larger needs a second person. This is the single most effective control and it is standard for a reason.
Require a reason code every time. Thirty seconds at the terminal, and it turns a number into information.
Review weekly, not monthly. A pattern caught in week one is a conversation. Caught in month three it is a much harder conversation about a larger number.
Tell your team you look at it. Openly, as a normal management practice rather than a suspicion. A control everyone knows about prevents far more than one that catches people afterwards.
What comps should be used for
They are a tool, and used well they are cheap.
A genuine mistake, fixed immediately. The most valuable comp there is. A guest whose problem was solved on the spot rates the experience higher than one who had no problem.
A long wait, acknowledged before the guest raises it.
A regular, occasionally. Not systematically — a discount that becomes expected stops being a gift and becomes your new price.
What they should not be is a reflex for every complaint. A server who comps first has not found out what went wrong, and you have paid for the food and learned nothing.
Where it shows up in the numbers
Comps sit between gross and net sales, and they distort several things quietly.
Prime cost. The food cost was incurred and the sale was not. A rising comp rate looks like a food cost problem, which sends you looking in the wrong place. Prime cost covers the calculation.
Server performance. A server with high sales and high comps may be selling less than they appear to.
Menu analysis. A dish that is frequently comped is telling you something about the dish or the station that makes it, and it will not show up in a popularity report.
The one-line version
Separate voids from comps, require a reason, approve above a threshold, review by person weekly as a percentage of their sales, and tell everybody that is what you do.