Purpose

Duplicated Lines (%) shows a percentage of duplicated lines in the project code compared to a total amount of lines of code (LOC) on the project.

How metric helps

Some will argue that duplication is the worst coding sin because it perpetuates all the others. For instance, copying and pasting a block of code duplicates its bugs and potential bugs, its coding standards breaches, etc. Hence, increasing duplicated lines percentage can indicate such issues as bad design, lack of good inheritance structure or abstraction, copyright infringement and so on.

How it works

Chart Overview

Duplicate code lines are shown in % (Axis Y) and distributed over time (Axis Y) on the chart.

Each project child unit (can be set up in Project Configuration Wizard) in the legend is clickable, and shows/hides its percentage on the chart once clicked. The chart also adjusts a scale automatically to better fit the series shown on a screen.

Calculation Formula

Duplicated Lines (%) is calculated as Duplicated Lines / Total Lines * 100%.

RAG thresholds: Red > 20%, Amber > 5%, otherwise Green.

Data Source

Data for the metric can be collected from Sonar or any other project tracking/engineering tool.