A count-based win rate describes how often a submitted bid wins. A value-based measure describes the share of submitted value won. Label each measure and its denominator.
Define a submitted bid
Keep drafts separate from submitted bids. Record a submission date so a saved draft cannot silently enter the denominator.
Recognise the same project
When several bids refer to the same project, define whether the report measures bids or unique projects. Keep that rule visible to the reader.
Separate open and closed work
An undecided bid is neither won nor lost. State which outcomes belong in the measure and keep the underlying client results private.