Power-Interest grid (engagement)
Mendelow's 2×2 (1981) tells you how to communicate. High-power + high-interest get manage-closely. High-power + low-interest get keep-satisfied (don't surprise them). Low-power + high-interest get keep-informed. Low-power + low-interest, monitor.
RACI matrix (decisions)
RACI tells you who does what on a specific decision or deliverable. Responsible (does the work). Accountable (one person — owns the outcome). Consulted (input before the decision). Informed (told after). Use it where ambiguity would otherwise stall a decision.
| Decision | PM | Sponsor | Eng Lead | Legal |
|---|---|---|---|---|
| Scope change >10% | R | A | C | I |
| Architecture choice | I | I | RA | C |
| Vendor selection | RA | C | C | C |
| Privacy review | I | I | C | RA |
↳ the most common RACI mistake
Two A's on one row. Accountability must be a single person — if everyone's accountable, nobody is. Consulted and Responsible can be plural; Accountable cannot.
When to use which
- Power-Interest — for ongoing communication strategy. Reviewed quarterly.
- RACI — for specific decisions or recurring deliverables that keep getting stuck.
- Together: Power-Interest tells you who to talk to; RACI tells you who decides what when you're in the room.