Are the code reviews in your organisation wasting time? It might be. How do you know for sure?
The clearest clues of inefficiency are long meetings, too many checkers, overlapping checking and unclear checking responsibilities. In the worst case, inefficient reviews are actually counterproductive.
A sure sign of inefficiency in code reviews is a meeting where possible fixes are discussed elaborately. These kinds of meetings typically take a long time and waste most people's time. Design discussions don't belong in the code review process.
If more than four (4) people are involved regularly in the code review, it is very likely wasting time. Especially so if the checkers cover the same code looking for all kinds of problems. The checkers will find the same things many times over, when each finding should only need to be found once. If this overlapping checking goes on for some time, the 'laziest' checkers will assume that somebody else will find the findings they are seeing. They might even on purpose ignore certain findings because of that. Some findings will then slip through unnoticed.
You can avoid the overlapping even if all checkers have the same code lines to check. They can be given different rules to check for. As long as everybody's checking for everything in the same code, there will be overlapping. To clarify the checking responsibilities - making clear that each checker is the only one checking for certain things - is a correct step towards improving the efficiency of code reviews.
In Qualiteers Code Inspection, there are no meetings. There are only as many checkers as needed. Each checker has a clearly set individual responsibility. Each checker has either a different part of the code or completely different rules to check. No design details are discussed in a big round. The findings are delivered in writing with the possibility of further discussion if necessary. The Qualiteers Code Inspection is primed for efficiency.