You are assessing your development team's technical debt and want a metric that reflects the amount of technical debt. Which metric should you recommend?

The percentage of overall time spent on rework is the most direct and impactful metric for technical debt. Technical debt often manifests as code that is difficult to maintain, extend, or fix, leading to more time spent correcting or redoing work that should have been done correctly the first time. This metric quantifies the cost of that debt in terms of developer effort. The number of code modules is a size metric, not directly indicative of debt. The number or percentage of unit test failures might indicate current bugs or issues, but not necessarily the underlying structural or design problems that constitute technical debt.