jf-identification

Causal Identification (jf-identification)

When to trigger

• The paper makes a causal claim ("X causes Y") resting on a research design
• You rely on an instrument, a shock, a discontinuity, or a diff-in-diff and a referee will attack the exclusion/parallel-trends assumption
• Endogeneity (reverse causality, omitted variables, selection) threatens the headline result

Scope: corporate / empirical causal effects. For cross-sectional asset-pricing tests use jf-empirical-design.

JF's bar for identification

JF is the AFA flagship, general-interest, with a ~5% acceptance rate and ~33–45% desk rejection (afajof.org editor reports, accessed 2026-05-30). For a corporate/empirical paper, credible identification is usually the binding constraint — a clever question with a weak design is a classic JF desk reject. The design must convince a broad AFA readership, not just specialists.

Design audit

Design	Core assumption to defend	Standard JF attack to pre-empt
Natural experiment	Shock is plausibly exogenous & well-timed	Anticipation; confounding co-occurring events
Instrumental variables	Relevance + exclusion	"Why does the instrument affect Y only via X?"
Diff-in-diff	Parallel trends; no differential shocks	Pre-trends; staggered-adoption bias
RDD	No manipulation; continuity at the cutoff	Bunching; bandwidth sensitivity

• State the source of variation in one sentence in the introduction (JF rewards a clearly named shock or instrument).
• Show the identifying assumption is testable where possible (pre-trends, first-stage F, McCrary test) and put the full battery in the Internet Appendix (bundled in the same PDF; see jf-internet-appendix).
• Report economic magnitude, since JF writes for a general-interest reader.

Worked vignette — a staggered-regulation natural experiment

Illustrative numbers. A paper claims a disclosure regulation, rolled out across states in 2011–2016, causes treated firms to cut leverage; the DID shows book leverage falling 4.2 pp (t = 3.4). Walk it through JF's bar:

1. Name the variation in one sentence: "Staggered state-level adoption of Rule X gives treated firms a plausibly exogenous shock to disclosure costs" — the introduction's credibility hook for a broad-readership editor.
2. Defend the assumption: an event-study plot shows flat pre-trends before adoption; the full coefficient panel goes to the Internet Appendix.
3. Fix the staggered-adoption bias: a naive two-way fixed-effects estimate (4.2 pp) is contaminated by already-treated controls. Re-estimate with a modern estimator (Callaway–Sant'Anna or Sun–Abraham); the clean estimate lands at ~3.1 pp — report it and flag the TWFE bias.
4. Pre-empt anticipation: show no effect in the year before the law as a placebo.
5. Report magnitude: 3.1 pp on a ~30% mean is a ~10% relative move — say so, since JF prizes economically large effects over bare significance.

The editor sees a named shock, a defended assumption, the right estimator, and a magnitude that matters to the AFA readership.

Referee-pushback patterns and the JF-specific fix

Pushback you will hear	JF-specific fix
"Your TWFE DID is biased under staggered adoption"	Re-estimate with Callaway–Sant'Anna / Sun–Abraham; show both
"The instrument could affect Y through other channels"	Spell out the one channel; falsification on the alternative paths
"Treated and control firms differ at baseline"	Balance table + covariate-trend plot in the Internet Appendix
"The shock coincides with the 2014–16 oil bust"	Excluded-period re-estimation; industry × year fixed effects
"Is 3 points economically meaningful?"	Express as % of the sample mean and tie to a dollar magnitude

Calibration anchors for JF identification

• For a corporate/empirical paper, identification is typically the binding constraint: a first-order question with a fragile design is a classic flagship desk reject, while a less novel question with airtight identification can survive.
• JF expects the identification battery visible but not bloating the body — pre-trends, first-stage F, McCrary density, balance tables go to the Internet Appendix, with one or two decisive plots in the main text.
• Weak-instrument and modern-DID standards evolve; confirm the expected diagnostics against recent issues and current author guidelines.

Checklist

• Source of identifying variation named in one sentence
• Exclusion / parallel-trends / continuity assumption explicitly defended
• First-stage strength (IV) or pre-trend evidence (DID) shown
• Modern estimators used where staggered adoption applies
• Confounders and anticipation effects addressed
• Magnitude interpreted, not just significance

Anti-patterns

• A causal verb ("increases", "causes") with only conditional correlations behind it
• An instrument with a hand-waved exclusion restriction
• Two-way fixed-effects DID on staggered adoption with no modern correction
• A clever question whose design no broad-readership editor would send out

Output format

【Design】NE / IV / DID / RDD
【Source of variation (1 sentence)】...
【Key assumption + how defended】...
【Main threat pre-empted?】yes / no
【Magnitude】...
【Next step】jf-robustness