---
name: cps-theory-building
description: Use when building or sharpening the theoretical argument of a Comparative Political Studies (CPS) manuscript so it yields portable, testable comparative implications. Builds the mechanism and its observable implications; it does not run the empirics.
---

# Theory Building (cps-theory-building)

CPS rewards arguments that travel. A good CPS theory is a **mechanism with scope conditions** that
generates observable implications a comparativist can test in more than one setting. Theory can be
verbal-causal, formal/game-theoretic, or comparative-historical — but it must do more than label; it
must predict *what should differ across cases* and *when the mechanism turns off*.

## When to trigger

- Turning a comparative puzzle into a stated argument with implications
- A reviewer said the paper "lacks a theory," "is descriptive," or "the mechanism is a black box"
- Your finding has no portable claim — nothing another comparativist could import
- You need to specify scope conditions and the contrast with the rival from `cps-literature-positioning`

## What a CPS argument must deliver

1. **A named mechanism.** State the causal process in one sentence: *actor → incentive/constraint →
   behavior → outcome*. Give it a portable name so it can be cited and carried.
2. **Observable implications.** List 2–4 predictions, including at least one that **distinguishes your
   mechanism from the rival** (not just "outcome happens").
3. **Scope conditions.** Say where the mechanism should hold and where it should *fail*. A theory that
   predicts everything predicts nothing; scope conditions make it comparative and falsifiable.
4. **Comparative statics / variation.** State how the outcome should change as the key cause varies
   across cases or over time — this is what the design (`cps-research-design`) will exploit.
5. **Micro-foundations where the claim is macro.** If the argument is about regimes or systems, name the
   actor-level behavior that must hold for the macro pattern to obtain.

## Modes of theorizing in CPS

| Mode | Strength | Watch out for |
|------|----------|---------------|
| Verbal-causal | Accessible, flexible | vague mechanism, unfalsifiable scope |
| Formal / game-theoretic | Precise comparative statics | model-empirics gap; assumptions doing all the work |
| Comparative-historical | Process and sequence, path dependence | selection on the outcome; ad hoc periodization |
| Typological | Organizes variation | categories without a mechanism behind them |

## The portability test (CPS-specific)

Write one sentence: *"In a different region/regime — say ___ — the same mechanism predicts ___."* If you
cannot, the argument is a local description, not a comparative theory. Then write the **distinguishing
implication**: *"If the rival account were right instead of mine, we would see ___; my mechanism
predicts ___ instead."*

## Checklist

- [ ] Mechanism stated in one sentence, with a portable name
- [ ] 2–4 observable implications, at least one distinguishing the rival
- [ ] Scope conditions: where it holds and where it fails
- [ ] Comparative statics stated (how outcome moves with the cause)
- [ ] Micro-foundations supplied if the claim is macro-level
- [ ] Portability sentence written for a second setting

## Anti-patterns

- A label masquerading as a mechanism ("institutions matter")
- No scope conditions — the theory "explains" every case, so it is unfalsifiable
- Formal model whose comparative statics are never tested, or a loose analogy to the empirics
- Comparative-historical narrative that selects on the outcome
- A finding with no portable claim — nothing another comparativist could carry to a new case

## Output format

```
【Mechanism】one sentence: actor → incentive → behavior → outcome (+ portable name)
【Observable implications】incl. the one distinguishing the rival
【Scope conditions】holds where / fails where
【Comparative statics】how outcome moves with the cause
【Portability】a named second setting where it should also hold
【Next】cps-research-design
```

## Supplementary resources

- [`../../resources/exemplars/library.md`](../../resources/exemplars/library.md) — verified CPS papers with portable mechanisms
- [`../../resources/worked-examples/01-introduction.md`](../../resources/worked-examples/01-introduction.md) — argument stated early in CPS house style