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.

1. Observable implications. List 2–4 predictions, including at least one that **distinguishes your

mechanism from the rival** (not just "outcome happens").

1. 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.

1. 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.

1. 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

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 — verified CPS papers with portable mechanisms
• ../../resources/worked-examples/01-introduction.md — argument stated early in CPS house style