How do you estimate a ROI for clearing technical debt?

Question

I\'m currently working with a fairly old product that\'s been saddled with a lot of technical debt from poor programmers and poor development practices in the past. We are star

Answer 1

Sonar has a great plugin (technical debt plugin) to analyze your sourcecode to look for just such a metric. While you may not specifically be able to use it for your build, as it is a maven tool, it should provide some good metrics.

Here is a snippet of their algorithm:

Debt(in man days) =
    cost_to_fix_duplications +
    cost_to_fix_violations + 
    cost_to_comment_public_API +
    cost_to_fix_uncovered_complexity + 
    cost_to_bring_complexity_below_threshold


 Where :

 Duplications = cost_to_fix_one_block * duplicated_blocks

 Violations   = cost_to fix_one_violation * mandatory_violations

 Comments     = cost_to_comment_one_API * public_undocumented_api

 Coverage     = cost_to_cover_one_of_complexity * 
                         uncovered_complexity_by_tests (80% of
                         coverage is the objective)

 Complexity   = cost_to_split_a_method *
                         (function_complexity_distribution >=
                          8) + cost_to_split_a_class *
                         (class_complexity_distribution >= 60)