At its core, economics is the study of choice. It’s not just about money, stock markets, or complex charts. It’s about how we, as individuals and as a society, deal with a simple, unchangeable fact: we can't have everything we want.

This brings us to the most fundamental concept in all of economics: scarcity. Scarcity means that our wants are unlimited, but the resources available to satisfy them are limited. You might want a new video game, a trip to Japan, and a fancy dinner, but you likely don't have the time and money for all three right now. That's scarcity in action.

Because of scarcity, we are forced to make choices. Every choice involves a trade-off, which means giving up one thing to get another. Deciding to study for an hour means you can't use that hour to watch a film. A government choosing to spend more on healthcare might have to spend less on building new roads. These are all trade-offs.

Every trade-off has a cost. In economics, the true cost of something isn't just its price tag. It's the value of what you gave up. This idea is called opportunity cost.

Imagine you're at a café with just enough money for either a cup of coffee or a delicious pastry. You really want both, but you can only choose one. If you choose the coffee, the opportunity cost is the enjoyment you would have gotten from the pastry. It’s the next best alternative you had to forgo.

This concept applies to everything. The opportunity cost of sleeping in for an extra hour is the productive morning you could have had. The opportunity cost of buying a car might be the round-the-world trip you could have taken with that money.

So what guides our choices? Economists point to incentives. An incentive is something that motivates you to act, either by offering a reward (a positive incentive) or threatening a punishment (a negative incentive).

A shop offering a 'buy one, get one free' deal is using a positive incentive. You're more likely to buy the item because you get a reward. A fine for littering is a negative incentive. You're less likely to drop rubbish because you want to avoid the punishment.

Incentives are everywhere, shaping our behaviour in ways we might not even notice, from library fines to employee bonuses. Understanding them is key to understanding why people make the choices they do.

When economists analyse these choices, they use two different types of analysis: positive and normative.

Positive analysis is about facts and cause-and-effect relationships. It describes the world as it is, without any judgment. A positive statement can be tested with data, and it's either true or false. For example, "An increase in the price of petrol leads to a decrease in petrol consumption."

Normative analysis is about opinions and value judgments. It describes the world as it should be. A normative statement can't be tested with data because it's based on personal beliefs. For example, "The government should lower the price of petrol."

It's crucial to know the difference. Positive economics provides the facts to inform decisions, while normative economics deals with the ethical and value-based goals of those decisions.

Now, let's test your understanding of these foundational ideas.

Understanding these core principles—scarcity, opportunity cost, incentives, and the two types of analysis—is the first step to thinking like an economist. You'll soon see that they apply to nearly every aspect of your life.