Function flow_efficiency_percent 

pub fn flow_efficiency_percent(
    active_time: f64,
    total_elapsed_time: f64,
) -> Option<f64>

Flow efficiency: the percentage of total elapsed time that was active work.

Most software delivery pipelines, measured honestly, land between 10% and 25% flow efficiency (chapter 2.5) — wait time, not active effort, dominates. A low number is typical, not a sign of a broken team; it redirects attention from “work harder” toward “reduce queueing.”

Arguments

• active_time — time actively spent coding, reviewing, or testing.
• total_elapsed_time — total time from start to finish, including wait time, in the same unit as active_time.

Returns

Some(percentage) (e.g. 10.0 for 10%), or None when total_elapsed_time is zero.

Examples

use software_engineering::flow_framework::flow_efficiency_percent;

// 10 active hours out of 100 total elapsed hours: 10% flow efficiency.
assert_eq!(flow_efficiency_percent(10.0, 100.0), Some(10.0));
assert_eq!(flow_efficiency_percent(10.0, 0.0), None);