ECON101: ace the component, not just read the notes
Your complete guide to University of Wisconsin-Madison's principles of microeconomics course. See where the marks are, work real practice questions, and study with an AI tutor that knows ECON101.
Sia generates ECON101 practice questions, walks through scarcity and supply step by step, and quizzes you on the material the component that weights most heavily.
Worked example
A cinema has already spent $8,000 producing an advertising campaign that cannot be recovered. It is deciding whether to screen an extra late-night showing. The showing would bring in $600 in tickets and cost $450 in staff and electricity. Should it run the showing?
Identify what changes if the decision goes one way rather than the other. The $8,000 is spent either way, so it changes nothing.
The difference is $150, so running the showing leaves the cinema better off than not running it.
State the principle: decisions are made at the margin, on costs and benefits that respond to the decision.
The trap: Letting the sunk $8,000 into the calculation. It feels like it should matter because it was real money, and options one and three are both built on that instinct. Sunk costs are irrelevant precisely because no available choice changes them, and this is the single most tested idea in an introductory microeconomics course. classic slip!
Overview
What ECON101 is, and where it sits
ECON 101 is UW-Madison's introduction to microeconomics: the economic problems of individuals, firms and industries, with emphasis on value, price and the distribution of income. It carries 4 credits and is the entry point to almost everything else in the economics catalogue.
It is worth knowing what the course counts for before you enrol. The catalogue designates it Core General Education in Mathematics and Quantitative Reasoning, Quantitative Reasoning Part B, and Social Science breadth, and it satisfies Quantitative Reasoning Part A as a requisite. In other words this is a quantitative course by designation, not an essay course, and its published outcomes say so: students are expected to identify and apply mathematical models and to express relationships among economic variables verbally, graphically and numerically.
The outcomes also point at the two habits the course is really training. One is marginal and cost-benefit reasoning applied across varied settings. The other is reading a current news article and recognising, then critiquing, the economic argument inside it. Students who treat the course as vocabulary memorisation tend to be surprised by how much of the assessment asks them to apply a model to something they have not seen before.
Always treat your own course outline and the exam timetable as authoritative.
Difficulty & time commitment
Is ECON101 hard, and how much time does it take?
ECON101 is manageable if you keep a weekly rhythm and treat the back half as the main event. The pattern is consistent: it starts gently and steepens, and the heaviest assessment is the part that separates grades.
The difficulty curve and the assessment weighting point the same way: the back half is harder and worth more. Front-loading effort there is the highest-return decision in the course.
Is this course for you
Who tends to do well, and who tends to struggle
You will likely do well if
- You treat it as a modelling course, since two outcomes are explicitly about applying models.
- You practise moving between words, graphs and numbers for the same relationship.
- You read economic news with the course's tools rather than separately from them.
- You keep pace; large introductory courses move fast and rarely slow down.
You may struggle if
- You expected a non-quantitative social science elective.
- You memorise definitions instead of applying marginal reasoning.
- You skip graph work, which is where a large share of exam questions live.
- You wait for a syllabus to tell you what matters rather than reading the published outcomes.
- Rewrite every result you meet as a graph and as a sentence, then check they agree.
- Do sunk cost and marginal problems until the reflex is automatic; they recur all semester.
- Take one news article a week and write three lines on the economics in it.
- Learn what the course's designations require, since assessment is built to satisfy them.
Syllabus
The 8 topics, topic by topic
The exam-weight marker on each topic shows where the marks concentrate. The amber topics carry the highest exam weight.
T1 · Scarcity, opportunity cost and the economic approach
Learning outcome 1The founding ideas: what scarcity forces, and what opportunity cost measures. Everything later is an application.
T2 · Supply and demand
Course descriptionHow price and quantity are determined in a market, and what moves them.
T3 · Incentives and decision-making by households and firms
Learning outcome 2How each side of the market responds to incentives, which is what makes the model predictive rather than descriptive.
T4 · Marginal analysis and cost-benefit reasoning
Learning outcome 6The single most transferable technique in the course, applied across a variety of settings by design.
T5 · Mathematical models of economic questions
Learning outcome 3Setting a question up so it can be answered with a model, and reading the answer back out.
T6 · Expressing relationships verbally, graphically and numerically
Learning outcome 4The same relationship in three registers. Exam questions routinely move between them, which is where marks are lost.
T7 · Market failure
Learning outcome 1Where the market outcome is not efficient, and what that implies about intervention.
T8 · Critiquing economic arguments in the news
Learning outcome 5A stated outcome rather than an extra: reading a current article and saying what the argument gets right and wrong.
How it's assessed
Assessment structure
A component-by-component weighting breakdown is not published for this course. Rather than estimate one, we publish only what the course itself states. Check your current course outline for the exact percentages.
No component weighting is published. The university catalogue publishes course description, credits, requisites, course designation and learning outcomes, but not assessment weights, and instructor syllabi carrying them are set per section and per term. Rather than estimate a breakdown or reuse a superseded one, none is asserted here. Check the syllabus your instructor posts for this term. Not published in the catalogue. Format is set per section by the instructor.
How to actually pass it
A weekly rhythm, two checklists, and the traps to avoid
The course rewards consistency over cramming, and practice over re-reading. Here is the loop that works, then what to have nailed before each exam.
The weekly loop
Before the mid-semester checklist
- Scarcity, opportunity cost and the production trade-off
- Supply and demand, and comparative statics
- Elasticity and its consequences for revenue
- Marginal analysis applied to a decision
Before the final heaviest topics
- Firm behaviour and market structure
- Efficiency, and where markets fail
- Distribution of income as the course frames it
- Reading and critiquing an economic argument in the news
The mistakes that cost marks
Counting sunk costs. If a cost does not change with the decision, it is irrelevant to the decision. Introductory exams test this repeatedly.
Confusing movement along a curve with a shift of it. A price change moves you along; anything else shifts the curve. Mislabelling this invalidates the whole answer.
Reading elasticity as a synonym for slope. It is a proportional response, and the distinction is exactly what makes it useful for revenue questions.
Treating the graph as decoration. In this course the diagram is the argument, and a wrong diagram cannot be rescued by correct prose.
Formula & concept sheet
The vocabulary and formulas you must own
- Scarcity
- Unlimited wants against limited resources; the condition that makes economics necessary.
- Opportunity cost
- The value of the best alternative given up when a choice is made.
- Sunk cost
- A cost already incurred and unrecoverable, and therefore irrelevant to any current decision.
- Marginal analysis
- Comparing the additional benefit and additional cost of one more unit of something.
- Supply and demand
- The two relations whose interaction determines market price and quantity.
- Elasticity
- The proportional responsiveness of quantity to a change in price.
- Efficiency
- An allocation where no one can be made better off without making someone worse off.
- Market failure
- A situation in which the market outcome is not efficient, such as externalities or public goods.
- Distribution of income
- How the returns to production are shared among participants, a named focus of this course.
Common acronyms: {'term': 'QR-A / QR-B', 'def': 'Quantitative Reasoning Part A and Part B, the UW-Madison general education requirements this course relates to'} · {'term': 'L&S', 'def': 'College of Letters & Science'} · {'term': 'GenEd', 'def': 'General education requirement'}.
Where it fits
Prerequisites, related courses & why it matters
Requires satisfied Quantitative Reasoning Part A. Not open to students with credit for ECON 111.
Your ECON101 study toolkit
Study the course with Sia, not just read about it
Each tool already knows ECON101: your syllabus, your texts, and where the marks are. Grouped by how you study, from first contact to exam week.
FAQ
Frequently asked questions
How many credits is ECON 101?
Four credits. It is designated Core General Education in Mathematics and Quantitative Reasoning, Quantitative Reasoning Part B, and Social Science breadth, at elementary level.
What do I need before taking it?
Satisfied Quantitative Reasoning Part A. It is not open to students who already have credit for ECON 111.
Should I take ECON 101 and 102, or ECON 111?
ECON 111 is the accelerated treatment covering both, aimed particularly at the Economics: Math Emphasis major, and taking it precludes 101 and 102. The 101 plus 102 route is the standard one.
Is it a mathematical course?
More than students expect. Two of its published outcomes require identifying and applying mathematical models and expressing relationships verbally, graphically and numerically, and it carries a quantitative reasoning designation.
How is it graded?
The catalogue does not publish a weighting, and instructors set assessment per section. Your section's syllabus is the source for this term.
Is the course still running?
Yes. The catalogue records it as last taught in Summer 2026 and it appears in the 2026-2027 catalogue.
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