EC104A Intermediate Microeconomics

Class 1: Introduction

Dr. Colleen O’Briant

University of California, Riverside

Fall 2026

Today

  1. Who I am
  2. What this course is about
  3. How class and lab will run
  4. How you will be graded
  5. What to do before next time

About me

  • PhD in Economics, University of Oregon, 2024
  • Second year at UCR
  • Research: econometrics and machine learning, especially methods and models of individuals making choices over time and under uncertainty
  • Teaching: building classes with high standards and high support, and teaching with the Socratic method

Other courses I teach

Course Topic Prereqs When
EC005 Data Analysis None Fall
EC060 Engineering Economics None Winter
EC136 Empirical Financial Economics EC107 Spring
EC111 Machine Learning for Economics EC107 Summer, perhaps

If you like the way this class runs, you know where to find more of it.

Outside the classroom

  • Grew up right outside Washington, DC
  • Two dogs: Lila (golden retriever) and Roxy (australian shepherd)
  • Enjoying exploring Southern California with both of them

Where to find me

Office: 4106 Sproul Hall (the building closest to the parking lot, fourth floor)

Office hours: Mondays and Wednesdays, 3 to 4 pm, or by appointment

Email: colleen.obriant@ucr.edu

Come by. Office hours are for questions about the material, about the course, or just to say hi.

What this course is

A calculus-based sequence in microeconomic theory, in three movements:

Consumersbudget, preferences, utility, choice, demand, consumer’s surplus

Competitive marketsequilibrium, exchange, welfare

Producerstechnology, profit, cost, firm and industry supply

By the end, you will be able to derive demand from first principles, characterize a firm’s costs and supply, find a competitive equilibrium, and measure the welfare consequences of market interventions.

EC104B picks up where we stop: monopoly, oligopoly, game theory, and market failure (information, externalities, public goods).

Microeconomics keeps getting re-discovered

  • Scarcity, supply, and demand: Ibn Khaldun in fourteenth century North Africa, authors of the Chinese Guanzi, and Kautilya in the Indian Arthashastra.

  • Marginal utility: discovered independently at least three times in the 1870s (Jevons, Menger, Walras), none of whom knew Gossen had published it in 1854

  • Consumer theory: Eugen Slutsky (1915), Hicks and Allen re-derived it in 1934

It only takes some mathematics and careful thinking about trade. You already have the mathematics. In this class, we’ll do the careful thinking.

How class will run

I’ll use the Socratic method: all knowledge is already within you.

A course should simply be a series of questions to draw that knowledge out. I’ve written almost 60 for you: two, usually three per lecture, and one in every lab.

I hope you’ll find: an idea you work out for yourself is understood far more deeply than one you are told.

This only works if you’re in the room! Skip class or skip lab, and this class will be very challenging.

Thinking versus “studenting”

Most of what school rewards is not thinking. It is studenting: pleasing the teacher, gaming the system for grades, divining what will be on the test.

Those are skills, but they have little to do with thinking hard about the content.

In this class, we’ll practice thinking hard about economics every day. This will be very different from most classes you’ve taken, where the emphasis is on studenting over thinking.

Thinking in the Age of AI

For the first time in history, machines can solve all kinds of thinking tasks for us. Completely amazing, but early research says:

  • Students who practice math with AI do worse once it is taken away (Bastani et al., PNAS, 2025)
  • People who write with AI engage their brains less, produce undistinctive work, and barely remember what they wrote (Kosmyna et al., 2025)

Relying on AI makes our thinking muscles atrophy, and eventually we lose confidence in our own ability to think. What’s the solution? Practice thinking hard, the way we’ll do in this course.

How you will be graded

Percent Category
80 Five unit tests (16% each)
10 Lab participation
10 Rotating front row

Full details are on the Grading page of the workbook.

Unit tests

  • Five tests, 50 multiple choice questions each, on Canvas with Browser Lockdown
  • A one week window for each test; you choose when to take it
  • 75 minutes per attempt, up to 3 attempts, 24 hours apart; highest score counts
  • Feedback comes by topic, not by question, so you know what to review before your next attempt

To study: the “check your understanding” questions at the end of every class and lab page.

Labs

  • Random groups of three, standing at a whiteboard, one marker per group
  • The lab instructor presents the Problem of the Day, then circulates, but will not tell you how to solve it
  • Stuck? Talk it through, look at other boards, ask another group

You are evaluated on engagement, collaboration, and perseverance. Phones and laptops stay away.

Rotating front row

  • On your two assigned days, sit in the front row and share a desk whiteboard with a partner
  • I pose a problem, you get ten minutes, and I look over your shoulder
  • You do not need to solve it; I am looking for honest effort and staying engaged
  • Engaged in the front row means full credit for the day, whether or not you are called up

Each front row day is 5% of your grade. Your dates are listed by last name on the Grading page. Emergencies: email me with documentation and we will reschedule.

This Week

  • Read the Course Overview and Grading pages in the workbook
  • Look up your front row dates
  • Get the textbook
  • Go to Lab 1: The Market at your registered lab section
  • Class 2 (Wednesday): Budget Constraint. We start building the theory of the consumer based on defining mathematically what they can afford, given their income.

Questions?

4106 Sproul Hall · Mondays and Wednesdays 3 to 4 pm · colleen.obriant@ucr.edu