A general formula must take account of the number of parties taking part. The rapporteur has produced the following tentative formula, though this has not been fully thought through and must be treated with caution.

L = _____uv________ - ε where:
            N + up -1

- uv is the number of useful votes (ones that can be counted after taking account of the legal threshold)
- N is the number of seats in the constituency
- up is the number of useful parties (those allowed to take part because they have received useful votes)