フィリップス曲線
Phillips Curve / フィリップス・カーブ
The Phillips Curve helps assess inflation-employment trade-offs by clarifying the relationship between inflation and unemployment and the trade-offs between price stability and employment goals. It keeps scope and assumptions aligned.
The Phillips Curve describes the short-run relationship between inflation and unemployment, influenced by expectations and supply shocks. It specifies the unit of analysis and the assumptions behind that relationship, including inflation expectations and wage-setting behavior. The concept separates what is in scope (short-run trade-offs and expectation dynamics) from what is out of scope (long-run natural rate outcomes), so comparisons stay consistent. Applied well, it turns a vague debate into a measurable choice and makes the drivers of results explicit.
Use the Phillips Curve to decide policy trade-offs, because it exposes inflation-unemployment dynamics and the trade-off with price stability versus employment goals. It changes budgeting and prioritization by making inflation expectations and wage dynamics explicit and reviewable. It informs adjustments when expectations de-anchor or supply shocks occur, so the decision stays grounded in current conditions.
- Use the Phillips Curve to decide policy trade-offs, because it exposes inflation-unemployment dynamics and the trade-off with price stability versus employment goals.
- It changes budgeting and prioritization by making inflation expectations and wage dynamics explicit and reviewable.
- It informs adjustments when expectations de-anchor or supply shocks occur, so the decision stays grounded in current conditions.
- Define the unit and time horizon before comparing inflation-unemployment dynamics across options.
- Track the primary driver (inflation expectations) separately from secondary noise.
- Run sensitivity checks on shock persistence and wage responses to avoid false precision.
- Document data sources and calculation steps so results are auditable.
- Revisit the model when the business model or market context changes.
A central bank models inflation at 3% with unemployment at 4.5% and compares a slow tightening path versus a faster one. They estimate how expectations respond to a 25 bp rate increase and test supply-shock scenarios. The analysis suggests expectations are drifting, so they tighten gradually while communicating a clear target. After implementation, they monitor wage growth and survey expectations to recalibrate the curve.
Compare Phillips Curve with adjacent concepts before deciding. Phillips Curve | Current concept | Use when the team needs the primary decision lens Adjacent metric or framework | Supporting lens | Use when the team needs evidence or process detail General vocabulary | Broad explanation | Use only for orientation, not final decision-making
| Metric | Difference | Why read together |
|---|---|---|
| Phillips Curve | Current concept | Use when the team needs the primary decision lens |
| Adjacent metric or framework | Supporting lens | Use when the team needs evidence or process detail |
| General vocabulary | Broad explanation | Use only for orientation, not final decision-making |
- The Phillips Curve is not stable over time; it can shift.
- It does not imply a permanent trade-off in the long run.
- Supply shocks can break the expected relationship.
When should I use Phillips Curve?
Use it when the team needs to decide scope, priority, owner, or trade-off, not when it only needs a short definition.
What makes Phillips Curve useful in practice?
It becomes useful when it is tied to evidence, a decision owner, and a concrete next operating choice.
What should I avoid?
Avoid using the term as a label without clarifying assumptions, boundaries, and how success will be judged.