JMP Introduction

The first paragraph should use sentences that are broad enough to tell the story, but narrow enough for the audience to know what exactly your story is going to be about (banking? information? public debt markets? volatility?). It should have the following structure

  • Here is the main question.
  • Here is what the literature says about it.
  • Here is the gap in the literature.
  • Here is why the question or the gap is important, interesting, or — ideally — both. (Hopefully you don’t need to state this explicitly.)

The second paragraph should start off with a sentence to the effect of, “Here is what I do to address this gap in the literature.” Describe concisely your identification strategy and data, but save knitty gritty details for later.

JMP Introduction

The Role of Household Misreporting on Mortgage Applications in the Financial Crisis

Misreporting of household income is an as-of-yet-understudied driver of the Financial Crisis. The basic argument is that some borrowers were able to obtain loans that they could not pay back, because they exaggerated their incomes on their loan applications. Two recent papers published in the Journal of Finance (1) document that some borrowers indeed misreported their incomes before the crisis, (2) find that borrowers who misreported were more likely to default post-crisis, even after controlling for observable borrower risk characteristics, and (3) explore why people might misreport.

Using loan applications from an unnamed U.S. Bank, Garmais (2015) first shows that loan applicants tended to round their incomes up to the nearest multiple of $100,000 in order to obtain larger loans. Then, he finds that (1) counties in which a greater fraction of loan applicants inflate their incomes have higher mortgage default rates, and (2) misreporting is more common in counties with a greater fraction of non-U.S. citizens, non-English speakers, and homeowners that probably have experienced negative home equity. (Misreporting is not correlated with the fraction of married or college-educated people.) From his second result, he deduces that misreporting is more common in areas with lower financial literacy and social capital. Overall, he concludes that financial illiteracy drives both misreporting (applicants misreport because they don’t know the value of their assets) and default.

Using loan origination documents from New Century Financial Corporation (New Century), Ambrose, Conklin, and Yoshida (2016) (ACY) largely corroborate Garmais’s findings; they find that applicants who could but did not verify income (1)  exaggerate their incomes by a greater amount and (2) are more likely to default. (Income exaggeration is estimated by (1) regressing actual income on borrower characteristics for those with verified income; (2) predicting income for non-verified borrowers using the estimates from (1); (3) taking the difference.) Importantly, these results hold only for non-verified borrowers that submitted W-2 forms, not for self-employed borrowers. ACY argue that misreporting is borrower-specific, not common to people in the same industry.

Pros and Cons of Regulation

  • Garmais: Limiting loans to applicants who report incomes right above multiples of $100,000 can exclude borrowers that misreport their incomes at the expense of excluding some creditworthy borrowers.
  • ACY: Banning low-documentation loans (loans originated to borrowers with little documentation to verify, for example, income) can mitigate adverse selection at the expense of excluding creditworthy self-employed people, the target market for these loans. (Banks developed low-documentation (low-doc) loans in order to serve self-employed people, for whom income verification is costly and who are less likely to misreport, because poor reputations limit future credit availability. )
The Role of Household Misreporting on Mortgage Applications in the Financial Crisis

How to Write an Introduction

First paragraph – The main question

  • The first sentence should answer, “what is the key economic friction this paper addresses?”
    • Zoom out as much as possible. You want your first line to appeal to the the widest audience possible.
  • (Explain why the implications of the friction X on outcome Y are not immediately obvious in three sentences:
    1. “The implications of X on Y are not immediately obvious.”
    2. “On the one hand, <bright side>”
    3. “On the other hand, <dark side>”)
  • State why the friction is important
    • Academically, is this a question academics are still stumped on or debating over? (If so, refer to above bullet point) Is this a nascent field on which we lack intuition?
    • Normatively, was a major law just passed or revoked? Was there a major event or troubling trend in an industry?
  • (If it fits here, state why the friction is urgent.)

Second paragraph – The setting

  • What is your setting?
    • “To address this issue, I look at …”
  • Why is it a reasonable, if not the ideal, laboratory to address the question you posed in the first paragraph?
  • (If it fits here, state why the friction is urgent.)

Data and Identification paragraphs

  • Use two or three paragraphs for these two topics.
  • If the data is novel, state that first, then describe how you use it to construct your identification strategy. Ideally, identification in previous papers was limited by their data, and, in contrast, your data allows you pursue the ideal (or close to ideal) identification strategy.
  • If the identification is novel, state that first, and describe what data you use to pursue it.

Results and Implications

  • What are the key results you want your readers to remember? State both the direction and magnitude in the simplest terms possible.
    • “A $y (y%) increase in Y leads to a $x (%x) decrease in X).
  • What are the implications for the issue in your first paragraph, i.e. what is so important about your findings?
    • Is the magnitude or direction surprising, i.e. do they overturn or corroborate intuition?
    • Do your results favor one argument/mechanism over another? Better yet, do they reconcile contradicting predictions?
  • Ideally, your results are simple enough to remember, even if they are rich enough to qualify different arguments.
How to Write an Introduction

Financing Spurs Employment Growth

Finance and Growth at the Firm Level: Evidence from SBA Loans
Brown and Earle, JF 2017

Main Question (General and Specific) and Results
This paper studies the real effects of finance. Specifically, it looks at how loans partially guaranteed by the Small Business Administration (SBA loans) generate jobs. It finds that jobs increase by 3-3.5 at the firm-level for each $1 million in SBA loans, which translates to a taxpayer cost of $21-25K per job.

The main contribution is the data: the authors have micro-level loan data with a long times-series and a sizeable cross-section. Previous studies relied on coarser approximations, such as the effect of SBA credit supply on county-level employment, or used micro-data that is limited cross-sectionally or in the times-series.

The authors match firms that received SBA loans with those that did not based on age, industry, size, year, and growth history, made possible by the richness of their micro-data.

To address selection into receiving an SBA loan and the amount obtained, the authors rely on institutional details. Lenders that obtain preferred lender status (PLP) in the Preferred Lender Program are granted lower administrative costs when they obtain partial loan guarantees through the SBA program.  This gives rise to an all-or-nothing participation strategy at the bank level. Indeed, “a large share” of all SBA loans are generated by PLP lenders. SBA loans account for only 1% of total bank business, making it unlikely that SBA demand drives banks’ locational decisions. This is important because SBA lending is highly local — 96.8% of SBA loans are given to borrowers in counties in which there was at least one PLP lender. PLP lenders are dispersed unevenly throughout the county and change over time, strengthening identification.

The conclusion, that financing has real effects, has been found in previous papers (e.g. Chodorow-Reich, QJE 2014; Mondragon, 2015). This paper corroborates the existing literature by looking into a specific institutional setting, SBA loans.

Financing Spurs Employment Growth

Physics, Philosophy, and Scientific Progress — Einstein

A great little find, words of wisdom regarding Physics, Philosophy, and Scientific Progress from Einstein in his address to the International Congress of Surgeons. I caught a glimpse of the printed version in a book at the International Museum of Surgical Science​ earlier today and found the full version when I got home

Words that really struck me — and some thoughts:
“Thinking alone can never lead to any knowledge of external objects. Sense perception is the beginning of all research, and the truth of theoretical thought is given exclusively by its relation to the sum total of those experiences” — I think theory for theory’s sake if fine — it can be beautiful and, though its applicability to the real world may not be immediately obvious, it can spark some idea or become a tool in solving real world problems. But for the most part, I have more assurance in the relevance of theory grounded in empirics.

“Specialization in almost all branches of human endeavor has, to be sure, resulted in unprecedented achievements–however, at the expense of narrowing the individual’s field of vision… as every graduate student knows.” “If some part of the human body has gotten out of gear, a person with sound knowledge of the whole complex organism is needed to put it right.” — PhDs are often recommended to find a niche and occupy it as the expert, but it’s important to keep the broader picture in mind.

Click to access einstein.pdf

Physics, Philosophy, and Scientific Progress — Einstein

Theory AND Empirics (Not Theory OR Empirics)

No one cares what your empirical results are if they don’t overturn/corroborate some economic/financial theory.

Likewise, no one cares about your fancy model and its complicated solution if it doesn’t address a real-world problem.

You can’t escape the real world by burrowing into theory, and you can’t circumvent theory by digging into data. A solid paper needs to be strong on both dimensions.

Theory AND Empirics (Not Theory OR Empirics)

Capital Structure as a Strategic Variable: Evidence from Collective Bargaining (Matsa, JF 2010)

Corporations intentionally cash-constrain themselves by levering up in order to gain bargaining power over labor unions. When unions come knocking at the door, they can throw their hands up and say, “Increase your wages? We barely have enough cash to pay off our interest payments!”

The paper addresses the larger question: What determines capital structure? Most mechanisms in the literature had revolved around taxes (e.g.firms might lever up because they pay less taxes on debt than on equity) or unobservable effort (e.g. keeping managers on a tight leash mitigates information asymmetries between the firm and investors).

In contrast, Matsa’s mechanism is novel and interesting because it pertains to the real activity of the firm.

Find the paper here

Capital Structure as a Strategic Variable: Evidence from Collective Bargaining (Matsa, JF 2010)