Mentor Session 8 — “Defending a result: what a referee actually asks.”
Week 8 live session · 60 minutes · led by Prof. Lei Gao · ASSIP’s final mentor session before the Aug 12 symposium
Eight weeks ago you computed an average return and thought you had an answer. Today you have a result — a number you can defend sentence by sentence, with a design behind it and an uncertainty attached. So today we close the arc by teaching the last skill ASSIP owes you: what happens after the result exists. Yesterday’s chapter (8.4) put you on both sides of the referee’s desk — writing a report, then answering one in writing. But the place a result is actually judged is not on paper; it is live, in a room, when someone who wants to disbelieve you starts asking questions and you have six seconds to answer. That room is the ASSIP Research Symposium on Wednesday, August 12, 2026 — the in-person poster session for on-campus interns, the virtual breakout track for our remote group — where Mason faculty, your peer mentors, your families, the College of Science leadership, and a roving photographer from Mason News will walk up to your poster and ask you the things they would ask any researcher whose work they doubt for the right reasons. That room is Assessment 8, the capstone defense. And that room is every research seminar I have sat in for twenty years, where the same handful of questions get asked of every paper, mine included. The single biggest predictor of whether a result survives is not how clever it is — it is whether the person who found it knows, before anyone asks, exactly where it is weakest, and can say so out loud without flinching. Bring the pre-read, your written warm-ups, and — this is the one that matters — your own capstone’s threats-and-responses table from Chapter 7.5. By the end of the hour you will have stress-tested your own result against a live referee, which is to say, against me.
(a) Pre-read packet — “The referee is looking for the reason not to believe you.”
Read this once before the session. It is one page; read it slowly, because this is the mindset I want in the room.
Here is the thing nobody tells you until you have published a few papers, so I will tell you now: a referee is not trying to understand your result. A referee is trying to find the reason not to believe it. That sounds adversarial, and in a sense it is — but it is the most useful service in all of science, and once you stop taking it personally it becomes the thing you cannot work without. The referee’s whole job is to stand between your claim and the permanent record and ask, on behalf of every future reader who will cite you without checking: is there a more boring explanation for this number than the one the author is selling? Almost always there is at least a candidate. Your job in the defense is not to pretend there isn’t — it is to show you found that candidate first, looked it in the eye, and either ruled it out or honestly bounded how much it could matter.
So what does a referee actually ask? After refereeing and presenting for two decades, I can tell you that the hard questions in empirical finance collapse into three families, and they come in this order of danger.
The first and deadliest is identification. This is the question of whether your comparison is fair — whether the difference you measured between treated and untreated, before and after, high and low, is caused by the thing you claim or by something tangled up with it. “Isn’t this just picking up [some confounder]?” is the identification question wearing its everyday clothes, and it is the question that kills papers, because if the comparison was never clean, no amount of careful estimation rescues it. A precise standard error on a confounded coefficient is a precise estimate of nothing. This is the row at the top of your Chapter 7.5 table, and it is the question I will ask first.
The second is robustness — the question of whether your result is fragile. Granting the design, does the number survive the arbitrary choices you made along the way? A different sample filter, a different control set, a different cutoff, a different flavor of standard error, a different window? “Does this hold if you [change that one choice]?” The referee asking this suspects you searched, even quietly, for the specification that gave the prettiest answer — the garden of forking paths from Chapter 7.3 — and wants to see the result is not balanced on a single knife-edge decision. This is survivable in a way identification is not: a robustness attack moves a number; an identification attack removes a comparison.
The third is alternative explanations — the question of whether a different mechanism produces the same data. Your story is one of several stories consistent with the pattern, and the referee wants to know why yours. “Couldn’t [this other channel] generate exactly what you see?” The defense here is rarely to deny the alternative; it is to find the place where your story and theirs make different predictions, and show the data sides with yours.
Internalize the ranking, because it tells you where to spend your scarce composure: identification is fatal, robustness and alternatives are usually survivable. And hold one reflex sharp as you read today’s questions — for my own result, what is the one reason a hostile, intelligent reader would have not to believe it, and have I already written down my answer? If you have, the defense is just reading your own script back. If you haven’t, that gap is the most important finding of the session.
(b) Three Socratic warm-up questions
Come with a written sentence or two for each. These have honest answers and evasive ones, not right and wrong ones.
The referee’s real question, decoded. A referee writes: “I worry the effect is driven by pre-existing differences between your treated and control groups.” Translate that single sentence into plain English — what are they actually accusing your design of? — and then name which of the three families it belongs to (identification, robustness, alternative explanation). Now the harder half: in one sentence, what is the single piece of evidence you could put on a slide that would do the most to answer it, and why does producing that evidence beat arguing with the referee in words?
Survivable or fatal — tell them apart in six seconds. Here are two questions you might get in your defense: (i) “Did you cluster your standard errors at the right level?” and (ii) “Couldn’t the same event that you call your treatment also have changed who is in your sample?” One you can answer with “we checked; it doesn’t move,” and one, if the questioner is right, sinks the paper. Say which is which, and state the general test — in one sentence — that lets you classify any incoming question as survivable or fatal while it is still being asked. (Hint from Ch 8.5: does it attack a number, or the comparison?)
The honest “I don’t know.” You will get a question you cannot answer; everyone does. Write the bad version of your answer (the bluff — a number or a claim invented on the spot) and then the good version (the located “I don’t know”). What three things does the good version contain that the bluff doesn’t — and why does a room full of people who do this for a living trust your other answers more after you admit this one limit, not less?
(c) Five-slide deck (speak-from scaffold)
Slide 1 — “The referee wants a reason not to believe you.” - After the result exists, the game changes: the room is not trying to understand your number, it is trying to find the more boring explanation for it. That is the job, and it is the most useful service in science. - The defense is not pretending no such explanation exists. It is showing you found it first, looked at it, and either ruled it out or honestly bounded it. - Three families of question, in order of danger: identification (is the comparison fair?), robustness (is the number fragile?), alternative explanations (does a different mechanism fit the same data?). - You already did the work — in your Chapter 7.5 threats table. The defense is reading your own script back to a room. Today we rehearse that, on your real result.
Slide 2 — Identification: the fatal family. - “Isn’t this just picking up [confounder]?” is the identification question in everyday clothes — and it is the one that kills, because a confounded comparison was never clean and no estimation rescues it. - A precise standard error on a confounded coefficient is a precise estimate of nothing. This is why identification sits above robustness, always. - The pattern of a strong answer: name the threat (so you don’t look surprised) → say what we’d see if it were true → show what we actually see → state the residual you still can’t rule out. That order makes you look like you saw it coming, because you did. - The selection version, which you will all face: my subjects didn’t get the treatment randomly — so why isn’t the result just selection? Hold that; it’s the spine of today’s stretch questions.
Slide 3 — Robustness & alternatives: usually survivable. - Robustness = “does it hold if you change that one choice?” The referee suspects you searched for the prettiest spec. Answer with the specification curve from Ch 8.1 — a tight cluster, not one number — and one sentence: “stable across the three choices I worried about most.” - Alternative explanation = “couldn’t [other channel] produce the same data?” Don’t deny it; find where your story and theirs make different predictions, and show the data sides with you. - The tell that separates these from identification: they attack a number, not the comparison. A moved number is a wound; a removed comparison is a death. - Pre-empt them on the slide so they’re answered before they’re asked. The robustness slide is a pre-emptive strike, not an appendix.
Slide 4 — When the critique is fatal and the attacker is right. - It happens. The instinct is to argue harder. That is exactly wrong — defending a broken design in front of a room that can see it is broken turns a damaged paper into a damaged reputation. - The move: concede at the level the point was made, and retreat to what survives. “You’re right I can’t rule that out with this design — so the honest reading is a strong association consistent with the mechanism, not the clean causal estimate I’d hoped for.” - Almost always there is a retreat position: fatal to the causal claim is rarely fatal to the descriptive one. “A robust pattern future work with [the better design] should test causally” is real, honest, publishable. - Know your retreat position before you walk in. That is what the residual-concern column of your threats table was for. A conceded fatal critique is a wounded paper but an intact scientist.
Slide 5 — Now defend your own. - You walk in with your capstone result and your Chapter 7.5 threats table. You walk out having defended it against a live referee — me — and having found the one question you could not answer cleanly. - Your capstone is graded on the defense, not the cleverness (Assessment 8). In the 8-minute talk, the eight minutes are the easy part; the question period is where the result is judged. The questions are your own threats-table rows, fired back at you. - The strongest sentence you can say to a hostile question about a number: “the exact code that produces it is in the packet — clone it and you get the same figure, seed and all.” You invite verification instead of asking for trust. That is the posture of someone with nothing to hide. - The reflection prompt makes you write the three hardest questions you’ll face — and your drafted answers — before the conference, when you’re calm. Bring it to your defense.
(d) Three “stretch” questions — defending a disclosure result against a referee
These tie today’s theme to a paper of mine, offered as a live worked case in exactly the spot where a referee presses hardest: a result about CEO behavior where the CEOs plainly did not get their characteristics assigned at random. The citation, used verbatim:
Elnahas, A., Gao, L., Hossain, M. N., & Kim, J-B. (2024). CEO Political Ideology and Voluntary Forward-Looking Disclosure. Journal of Financial and Quantitative Analysis, 59(8), 3671–3707.
The paper asks whether a CEO’s political orientation — broadly, whether the executive leans conservative or liberal — relates to how the firm they run discloses information: how much, how forthcoming, how transparent the firm’s communications to the market are. The reason this is the perfect case for today is that it sits squarely in the crosshairs of all three referee families at once. A skeptic’s first reaction is immediate and correct: CEOs are not handed their politics at random. The kind of person who becomes a conservative-leaning CEO may differ from a liberal-leaning one in a hundred ways — the industry they rose through, the firm that hired them, their age, their risk appetite — and any of those could drive disclosure directly. That is selection, and it is the single hardest thing this paper had to defend.
Reason about measurement, identification, selection, and how a defense is built — not about what the paper specifically found. Do NOT invent or recite any specific reported magnitudes, coefficients, sample sizes, t-statistics, or named control variables from the paper. Frame every answer as “how a disclosure outcome could be measured,” “what a referee would demand,” or “how I would defend it.” Mark anything you would need to confirm against the actual paper as [CHECK].
Measuring the outcome — what number goes in the y column? Before a referee can attack identification, they attack measurement, because if “information disclosure” isn’t a real number, there is nothing to defend. (a) “Information disclosure” is a concept, not a series. Propose two distinct, defensible ways a researcher could turn “how forthcoming is this firm’s communication” into a measurable variable on a firm-year — and for each, name one thing a referee would worry the measure is secretly capturing instead of disclosure (a mechanical confound: firm size, industry reporting norms, litigation exposure). (b) A referee’s classic measurement challenge is: “Your disclosure measure and your politics measure could both just be proxying for something else — how do I know you’re measuring what you say?” In the language of today, which family does that belong to, and what is the cheapest convincing response — a better measure, or showing the result holds across several different disclosure measures that share no common mechanical flaw? (c) [CHECK] the paper’s actual disclosure measure(s) and its proxy for CEO political orientation before describing either as fact — reason about what a good measure must do, not which one the paper uses.
The selection problem, stated and attacked. Here is the referee’s deadliest question, and it is the one every one of you will face in some form: “CEOs don’t get their politics randomly assigned. Isn’t your ‘effect’ just selection — conservative-leaning CEOs end up at a different kind of firm, and it’s the firm, not the CEO’s politics, doing the disclosing?” (a) State, in one plain sentence, the identifying assumption this kind of design needs to survive that question — what would have to be true about how CEOs sort into firms for the comparison to be fair? (b) Name two concrete robustness/identification moves a referee would demand to make the selection story less plausible — think about what we covered in Weeks 3–4: controlling richly for firm and CEO characteristics (and why “we control for it” is a claim, not a spell — the omitted-variable ghost from Week 2), firm fixed effects so the comparison is within-firm, or — the strongest move — finding variation in CEO politics that arrives for reasons plausibly unrelated to the firm’s disclosure tendencies (a CEO turnover event, a shock to the executive’s environment). For each move, say in one sentence what threat it kills and what it leaves standing. (c) Now the honest part: selection can rarely be killed completely with observational data. Following Ch 8.5’s retreat logic, what is the most a defensible version of this paper should claim — a clean causal effect of CEO politics on disclosure, or a robust association that survives the obvious selection stories — and why is claiming the second, honestly, stronger than overclaiming the first? ([CHECK] the paper’s actual identification strategy before asserting which of these moves it used.)
Building the defense the way the authors had to. Step into the authors’ shoes at the revise-and- resubmit stage — exactly the R&R memo of Ch 8.4, now imagined for a real journal. A referee has raised the selection concern from Q2 and an alternative explanation: “This isn’t about politics at all — it’s about risk tolerance. Conservative-leaning executives are simply more risk-averse, and risk-averse managers disclose differently. You’ve relabeled risk aversion as politics.” (a) Why is that alternative-explanation attack more dangerous than a pure robustness complaint, even though it doesn’t attack the design directly? (Hint: it grants your number and steals your interpretation.)
- Describe the shape of a convincing answer — not the paper’s actual one, which you should [CHECK] — using today’s rule: find a place where “it’s politics” and “it’s just risk aversion” make different predictions, and let the data choose. What kind of test would split those two stories?
- Tie it back to honesty: a referee will never be fully satisfied that politics, risk aversion, and a dozen correlated CEO traits are perfectly disentangled. Where, exactly, does that residual concern belong in the final paper — buried, or stated plainly in the limitations — and why does the author who writes “here is the trait I still can’t fully separate out” get believed more than the one who claims a clean sweep? (Frame everything as “how I would defend it”; borrow no magnitudes.)
(e) Post-session reflection prompt
Write ~250–350 words after the session. This is the one that goes with you into Assessment 8 and the conference — write it as if your defense depended on it, because it does.
Write your defense brief for your own capstone. Open your Chapter 7.5 threats-and-responses table, your robustness results from Chapter 8.2, and your one-click packet from Chapter 8.5, and then do the thing this whole session was pointed at: anticipate the three hardest questions a referee will ask about your result, and draft your answer to each in full. For every one of the three, write four lines. First, the question itself, phrased the way a hostile, intelligent reader would actually say it — not a softball; the real one, the one you hope nobody asks. Second, classify it: is this identification (fatal if lost), robustness (a number that might move), or an alternative explanation (someone stealing your interpretation)? Be honest, because the classification decides how hard you fight. Third, write the drafted answer in the four-beat shape from Slide 2: name the threat so you don’t look surprised, say what you’d see in the data if it were true, show what you actually see (point to the table, figure, or robustness column — the real number), and state the residual concern you cannot fully rule out. Fourth, and only for whichever of the three is genuinely fatal if the attacker is right: write your retreat position — the claim that survives even if you lose the point, almost always the honest descriptive version (“a robust association future work should test causally with [the better design]”), so that a conceded critique leaves you a wounded paper and an intact scientist rather than nothing at all.
Then close with the two sentences that are the whole point of eight weeks. The first is the question I will actually ask you in your defense, so have the answer ready: “What is the single best reason, right now, not to believe your result — and what did you do about it?” The second is the sentence this camp existed to let you say truthfully, the one that turns a claim into a result and ends the arc that started with an eight-percent average: “Here is what I found, here is exactly why you should believe it, and here is the one command that lets you check me.” If you can write both sentences honestly, you are not a student who took a finance course. You are a researcher who can defend a result. Go defend it.