Economic Jargons

Here I list important economic jargons that I encountered during my studies

Key Terminology

• Model completeness

  Model Incompleteness refers to situations in econometric analysis where the structural model specified by the researcher does not fully characterize the data-generating process, leaving critical aspects of agents’ behavior, institutional rules, or information structures unmodeled. This incompleteness can arise when key assumptions required for point identification (e.g., equilibrium selection rules, precise functional forms, or strict rationality) are either unavailable or intentionally relaxed to avoid over-restrictive specifications.

  In their seminal 2003 Econometrica paper, Haile and Tamer examine model incompleteness in the context of ascending auctions (e.g., English auctions). They highlight that traditional structural models of auctions often rely on strong assumptions, such as exact equilibrium bidding strategies (e.g., Nash equilibrium) or full specification of bidders’ beliefs. However, these assumptions may not hold in practice, leading to partial identification rather than point identification of parameters like bidders’ private valuations.

key Latin terms

1. Ceteris Paribus
   • Translation: “All other things being equal.”
   • Use: A foundational assumption in economic models to isolate the effect of one variable while holding others constant.
   • Example: “If the price of coffee rises, ceteris paribus, demand will fall.”
2. Ex Ante vs. Ex Post
   • Ex Ante: “Before the event” (forward-looking analysis, such as expectations or forecasts).
   • Ex Post: “After the event” (retrospective analysis of outcomes).
   • Example: “Ex ante, investors predicted a 5% return; ex post, the actual return was 3%.”
3. Mutatis Mutandis
   • Translation: “With necessary changes having been made.”
   • Use: Comparing scenarios while adjusting for relevant differences.
   • Example: “The demand for electric cars, mutatis mutandis, mirrors the historical adoption curve of smartphones.”
4. Sui Generis
   • Translation: “Of its own kind” (unique or in a class by itself).
   • Use: Describing phenomena that defy standard categorization.
   • Example: “Cryptocurrencies are sui generis assets, blending features of currencies, commodities, and technologies.”
5. Homo Economicus
   • Translation: “Economic man.”
   • Use: A theoretical rational, self-interested agent in classical economics.
   • Critique: Contrasted with behavioral economics, which emphasizes bounded rationality.
6. Prima Facie
   • Translation: “At first sight.”
   • Use: Initial evidence or assumptions in policy or legal analysis.
   • Example: “A monopoly has prima facie market power, but regulators must prove harm.”
7. De Minimis
   • Translation: “About minimal things.”
   • Use: Thresholds for ignoring trivial effects in cost-benefit analysis.
   • Example: “Tariffs are waived for de minimis imports to reduce administrative costs.”
8. Ad Valorem
   • Translation: “According to value.”
   • Use: Taxes or tariffs calculated as a percentage of a good’s price.
   • Example: “A 10% ad valorem tax on imported luxury cars.”
9. Per Se
   • Translation: “By itself.”
   • Use: Identifying inherently harmful practices (e.g., antitrust law).
   • Example: “Price-fixing agreements are illegal per se under competition law.”
10. Ultra Vires
    • Translation: “Beyond the powers.”
    • Use: Actions exceeding legal or institutional authority.
    • Example: “Central banks acting ultra vires by funding fiscal deficits risk inflation.”
11. Tabula Rasa
    • Translation: “Blank slate.”
    • Use: Debates about human behavior (nature vs. nurture) in welfare economics.
12. Sine Qua Non
    • Translation: “Without which, not.”
    • Use: Identifying necessary conditions for economic outcomes.
    • Example: “Property rights are a sine qua non for market economies.”

• In econometrics: Terms like ex ante and ex post frame predictive vs. observed data.
• In policy design: Ceteris paribus simplifies complex systems but risks oversimplification.
• In legal economics: Prima facie and per se shape antitrust and regulatory frameworks.