Learn the economics of a new age — from first principles to the frontier.

Who really sets the price of things?

Supply and Demand Explained: How Markets Actually Set Prices

• Equilibrium in one picture
• Elasticity, and why taxes hit some goods harder

Why do prices keep rising?

Understanding Inflation: How Rising Prices Are Measured and Why They Matter

• How a price index tracks a basket of goods
• Demand-pull vs cost-push inflation

How does a central bank steer the economy?

Monetary Policy Explained: How Central Banks Steer Inflation and Growth

• The four channels a rate change travels through
• Rules versus discretion: the open debate

Why do economies boom and then slow down?

Business Cycles Explained: Why Economies Expand, Peak, Contract, and Recover

• Why no single number tells you the phase
• What the yield curve warns about

Does government spending really grow the economy?

Fiscal Policy and Multipliers: How Government Spending Moves the Economy

• Why multipliers are bigger in recessions
• What actually makes debt sustainable

What decides the value of a currency?

Exchange Rates Explained: How Currencies Are Valued in an Open Economy

• Why a weaker currency is good and bad news
• The trilemma no country escapes

Optimization and Lagrange Multipliers Explained: Choosing the Best Option Under a Constraint

• Constrained optimization finds the best choice when something is limited, such as a budget, a time allowance or an emissions cap; the Lagrange method turns that problem into a set of equations that can be solved directly.
• The Lagrange multiplier is not just a calculation device: it measures how much the best achievable outcome changes when the constraint is loosened by one unit, which economists call a shadow price.

Comparative Statics Explained: How an Equilibrium Responds When Something Changes

• Comparative statics compares two equilibria, before and after a change in something outside the model such as a tax rate, and measures how the outcome moves in response.
• The implicit function theorem turns that comparison into a formula, so the direction and size of the effect can be read from slopes such as supply and demand elasticities, without re-solving the model.

Linear Algebra for Economists Explained: Matrices, Eigenvalues and the Steady State of a Labor Market

• Linear algebra is the mathematics of many equations and many variables at once; economists use it to solve multi-market models, estimate regressions and track how populations move between states.
• A transition matrix built from Eurostat data on quarterly flows between employment, unemployment and inactivity predicts where the EU labor market settles: the long-run split of the population across the three states is the left eigenvector of the matrix for eigenvalue 1, and the long-run unemployment rate follows from that split.

How do economists measure the effect of one thing on another?

Understanding OLS Regression: How Economists Estimate Real Relationships

• What “least squares” actually minimises
• The four conditions that make the estimate reliable

Why can two unrelated trends look perfectly correlated?

Time Series Analysis Explained: Stationarity, Unit Roots and Cointegration

• Stationarity, unit roots and the Dickey–Fuller test
• Cointegration: real long-run relationships between trends

How do you compare a country with itself instead of with its neighbors?

Panel Data Explained: Fixed Effects, Random Effects and the Hausman Test

• Pooled OLS vs fixed effects vs random effects
• The Hausman and Mundlak tests

How do economists separate cause from confounding?

Instrumental Variables Explained: Endogeneity, 2SLS and Weak Instruments

• The UK’s 1947 school-leaving reform as a natural experiment
• Two-stage least squares and weak instruments

How do economists measure what a policy actually did?

Difference-in-Differences Explained: Measuring Policy Effects with Natural Experiments

• The New Jersey minimum wage natural experiment
• Parallel trends and the regression form

How do you forecast inflation, and how risky is tomorrow?

ARIMA and GARCH Explained: Forecasting a Series and Its Volatility

• Choosing p, d and q with ADF, ACF and AIC
• Volatility persistence and half-life

Consumer Theory and Duality Explained: Utility, Expenditure and the True Cost of a Price Rise

• Consumer theory models a household that picks the best bundle it can afford; duality shows the same choice can be described as the cheapest way to reach a given level of well-being.
• The expenditure function turns that idea into money: it measures how much income a household needs to stay as well off after prices change.

Producer Theory and Cost Functions Explained: How Firms Choose Inputs and What a Wage Rise Costs Them

• Producer theory models a firm that turns inputs into output and chooses the cheapest input mix for any output level; the cost function records the result.
• Shephard's lemma links the two: the slope of the cost function with respect to an input price is the amount of that input the firm uses.

General Equilibrium and the Welfare Theorems Explained: How All Markets Clear at Once

• General equilibrium studies all markets at once: a set of prices at which supply equals demand in every market simultaneously, taking account of how each market feeds into the others.
• The first welfare theorem says a competitive equilibrium is Pareto efficient; the second says any efficient allocation can be reached as a competitive equilibrium after lump-sum transfers.