Econ 101 lectures 1 Aug 26, 2025 - Key Points: Logistics, AI, PPF, and Core Concepts
Course logistics
Room capacity: seats; fully registered class; seats may fill quickly; three exits: back left, back right, front right.
Seating etiquette: move inward to keep outer seats accessible; be mindful of others when entering/exiting.
Fire drills/emergencies: use any of the three exits; be respectful of others during exits and when subsequent class starts.
Enrollment and waitlists:
Class capacity is full; if you're on the waiting list, you remain waiting for a specific discussion section, not the lecture.
There are 11 discussion sections affiliated with Lecture 400; monitor others because a section can fill or clear at different times.
You are enrolled in the lecture only after you are enrolled in a discussion section.
Canvas and course navigation
Use a web browser for Canvas; the mobile app has limited functionality.
Key sections on the Canvas front page:
Announcements, office hours, grades (via Gradescope), and question postings.
Weekly to-do pages with the week’s tasks, slides, and readings.
Writing resources and the course information (grading, policies, etc.).
Important modules and links:
Grading and assignments: where to find assignments and grading policies.
Resources: old tests, writing citations, and study materials.
Additional course information: class policy, reading materials, economics in the world, AI policy, health and well-being resources.
Office hours availability:
Instructor: after class on Tuesdays and Wednesdays (two hours total).
GSIs: six public hours (one per GSI) plus a private hour for each discussion section.
Writing fellows will also have office hours once fleshed out.
Announcements and course highlights
Every class starts with announcements: assignments, due dates, tests, and department events (e.g., Econ student orgs).
Economics at Work (Econ 208, Fridays at 01:00) is a separate class featuring alumni talks; consider enrolling if interested in careers with economics.
Assignments, quizzes, and policies
Quizzes:
Five quizzes in total.
Quizzes 1–4 scheduled on Wednesday evenings at 06:00; times are fixed and cannot be changed.
Quiz 5 occurs during finals period and is non-cumulative.
Writing assignments:
Three writing assignments across the semester; first opens September 9.
The course includes a citations and policies worksheet; you can take the related quiz multiple times until you reach full points (up to 21).
Grading and scale:
Department targets: approximately 45% of the class should receive an A and 85% should receive an A or B; the scale may be adjusted if actual outcomes deviate significantly.
Historically, the class tends to fall around 82–83% of students receiving A/A-B, with occasional adjustments to maintain the department target range.
No cumulative final; quizzes focus on the most recent material; difficulty may be adjusted mid-semester to avoid large downward adjustments.
AI policy:
AI research is conducted on writing assignments; you may opt out by Sept 18.
Do not copy-paste prompts into ChatGPT or submit AI-generated text; always cite AI-generated ideas or assistance when used; the goal is to assess your own understanding.
If you have questions about AI policy, ask and review the policy document.
Core economic concepts (brief recap)
Economics = the study of the allocation of scarce resources; scarcity forces choice.
Opportunity cost: what you must give up to obtain a chosen item or activity.
Costs and benefits: used in policy analysis; monetization is common but not required.
Models and ceteris paribus (all things equal): simplified representations with one changing variable at a time; allow understanding of cause-and-effect in a controlled setting.
Positive vs normative economics:
Positive: factual/descriptive statements about how the economy works (e.g., when price rises, quantity demanded falls).
Normative: value judgments about what should be done with that information.
Production Possibilities Frontier (PPF) and trade-offs
Simple two-good model (Tom the island) with:
Fish (F) and coconuts (C)
In one day, Tom can collect up to 40 fish or 30 coconuts (endpoints of the frontier).
The production possibilities frontier (PPF) shows all feasible (F, C) combinations using all daylight hours.
Feasible vs feasible & efficient vs infeasible:
On the frontier (e.g., point a or b): feasible and efficient (full use of resources).
Inside the frontier (e.g., point c): feasible but not efficient (resources underutilized).
Outside the frontier (e.g., point d): not feasible with current resources.
Increasing opportunity cost (concave to the origin):
As you shift from producing coconuts to more fish, the opportunity cost of additional fish rises (you give up more coconuts per extra fish over time).
Narrative example: catching fish from a tidal pool becomes harder as you deplete the easy catches; similarly, gathering coconuts becomes harder as you pick the closest ones first.
Sharp intuition: moving along the PPF demonstrates trade-offs; the slope indicates opportunity cost; steeper slopes mean higher marginal cost of fish in terms of coconuts, and vice versa.
Economic growth and outward shift:
Growth occurs when resources increase or technology improves, shifting the PPF outward (e.g., discovering a net enables more efficient fishing and gathering).
Growth can be broad (affecting both goods) or narrow (affecting one, though often cross-effects occur).
Straight-line PPF (constant opportunity cost):
A simplified case with constant OC where trade-offs are fixed; used to introduce more complex scenarios.
Next steps (preview):
Introduce a second person with a constant OC assumption to analyze how two agents interact and how the frontier changes.
Quick recap of key terms for last-minute review
Scarcity, opportunity cost, production possibilities frontier (PPF)
Increasing opportunity cost, concave PPF, feasible/efficient vs infeasible
Constant opportunity cost (straight-line PPF)
Models and ceteris paribus, positive vs normative economics
Economic growth, innovation, and education as growth factors
AI policy and the importance of original student work