---
title: Flow Analysis
type: method
tags: [bpm, quantitative-analysis, cycle-time, performance]
sources: ["[[sources/2018-dumas-fundamentals-of-bpm]]"]
created: 2026-04-13
updated: 2026-04-13
---

# Flow Analysis

Analytical technique for computing process performance measures directly from the process structure and per-activity durations, without simulation ([[sources/2018-dumas-fundamentals-of-bpm]], §7.1).

## Core calculations

### Cycle time (sequential blocks)
`CT = Σ T_i` — sum of activity durations along a sequential block.

### XOR blocks
`CT = Σ p_i × T_i` — probability-weighted average.

### AND blocks
`CT = max(T_i)` — longest parallel branch.

### Rework blocks
`CT = T / (1 − r)` — geometric expansion for a rework probability `r`.

## Critical Path Method (CPM) (§7.1.2)
The longest path through the process — determines the minimum achievable cycle time.

## Little's Law (§7.1.4)
`WIP = λ × CT`
(work-in-progress = arrival rate × cycle time). Connects throughput, queue length, and cycle time; central to capacity planning.

## Capacity and bottlenecks (§7.1.5)
Identify the resource with highest utilisation; cycle-time improvements upstream of the bottleneck don't help.

## Cost flow analysis (§7.1.6)
Same compositional rules applied to per-activity costs.

## Limitations (§7.1.7)
- Assumes deterministic or stable probabilistic structure.
- Ignores queueing dynamics (use [[methods/process-simulation|simulation]] or [[methods/process-simulation|queueing theory]] for those).
- Cannot model resource contention.

## Related
[[methods/process-simulation]] · [[concepts/devils-quadrangle]] · [[concepts/bpm-lifecycle]]