At GitLogger, we believe Knowledge is Power, and Standards are Good.
To that end, we have standardized how we derive metrics from git logs.
You can easily graph or query any named metric, and use them to help know your repos

MetricName	Synopsis	Description
AttachRate	Attach Rate by User	Gets the percentage of commit messages that reference an issue number or pull request.
BusyDayOfWeek	Busy Day Of Week	Shows total lines changed by day of week.
Churn	Average number of files in a commit	Gets the average number of files in a commit by a contributer
CommitCadence	Commit Cadence	Gets the total Commits per contributor and divides by their active timeframe.
CommitCount	Commit Counts	Gets the number of commits by each contributor.
CommitRepeats	Commit Repeats	Total Repeated Commit Messages by User
IssueBreadth	Issue Breadth	Gets the distinct number of issues mentioned in commits by user.
LineCadence	Line Cadence	The total number of lines changed per user, divided by the time between commits.
LinesChanged	Lines Changed	Lines Changed by a user
NetLineCadence	Net Line Cadence	The insertions-deletions changed per user, divided by the time between commits.
NetLinesChanged	Net Lines Changed	Total Insertions - Total Deletions by UserName