Course: Principles of Macroeconomics (ECON 2) · Silver Oak University (fictional sample) · Prof. Ashford
Focus: Economic Growth & Productivity · Objective 4 · SLO A & B

📋 Module Overview Page — "Start Here" (Canvas: Page, published)

Week 4 — Economic Growth & Productivity: Why Small Rate Differences Compound Huge

The last two weeks gave you a snapshot camera — GDP and the price/labor gauges tell you how the economy looks right now. This week we switch to a time-lapse camera. Long-run economic growth is the single biggest driver of whether a country is rich or poor a generation from now — and the tool that makes growth rates click, the rule of 70, is one of the most quietly powerful ideas in this course.

The big question: Why do tiny differences in a growth rate compound into enormous differences in living standards — and where does growth actually come from?

By the end of this week, you can:

• compute a growth rate from two GDP figures using the percentage-change formula, and read it correctly as growth (a flow, a rate) rather than a level;
• apply the rule of 70 to estimate how many years it takes an economy (or a savings account, or anything compounding) to double — and avoid the classic slip of multiplying instead of dividing;
• compute a rough per-capita growth rate (GDP growth − population growth) and explain why per-person living standards, not just total output, are what growth is ultimately about;
• name the three broad sources of long-run growth — physical capital, human capital, and technology — and describe the Solow growth model as the field's standard framework for organizing them (named factually, not derived).

Do this, in order:

1. Read & watch — the Week 4 resources (≈25 min). → Readings & Resources page
2. Lecture Tutorial — work through growth rates, the rule of 70, per-capita growth & the sources of growth with your AI tutor (≈45 min). Due Sun, Sep 27. → submit the chat share link + summary
3. Practice Exercises — 6 quick reps, ungraded (≈15 min).
4. Quiz 4 — 10 questions, closed to AI (≈20 min). Due Sun, Sep 27.
5. Discussion 4 — "Should policy aim to maximize growth?" Initial post Fri, Sep 25, replies Sun, Sep 27.
6. Assignment 4 — the growth-rate, rule-of-70 & per-capita problem set (100 pts). Due Sun, Sep 27.
7. Workshop 4 — Graph & Model Workshop — "Growth Rates & the Rule of 70": compound a small economy in a spreadsheet or Desmos and watch a small rate gap turn into a huge output gap (50 pts). Due Sun, Sep 27.

A note before you start: this week's math is genuinely simple — a percentage-change formula and one division, 70 ÷ rate. The payoff is what's hard to feel until you see it compound: a country growing at 2% and a country growing at 7% look almost the same after one year and wildly different after ten. That's the whole week in one sentence. 💪

📣 Welcome Announcement (Canvas: Announcement; available_from_offset_days = 0 — posts Mon, Sep 21)

Subject: Week 4 — the most powerful idea you'll learn all term is one division problem 👋

Hi everyone,

Quick question to open the week: would you rather have a country growing at 2% a year, or one growing at 7%? Obviously 7% — but how much better is it, over time? This week's answer will surprise you, and it comes from a tool called the rule of 70: divide 70 by the growth rate, and you get roughly how many years it takes the economy to double. At 7%, that's about 10 years. At 2%, it's 35. Same starting point, wildly different worlds a decade or two later.

This week, don't miss:

• Growth rates — the same percentage-change formula you've used before (Weeks 2–3), now applied to GDP over time instead of prices or a labor count.
• The rule of 70 — the single most useful shortcut in this course, and the #1 place people (and chatbots) slip: it's divide, not multiply.
• Per-capita growth — because a bigger economy with a much bigger population isn't necessarily a richer one, person for person.
• The sources of growth — physical capital, human capital, and technology, organized by the field's workhorse framework, the Solow growth model (we'll name it, not derive it).

Start with the Module Overview ("Start Here"), then the readings, then your AI Lecture Tutorial. Bring your calculator to class — today's worked examples are quick, but you'll want to do them yourself, not just watch.

See you in class,
Prof. Ashford