When you want a cup of coffee, the process is simple. You check the price, decide if it’s worth it, and buy it. If the price doubles overnight, you might buy less. If it’s on sale, you might buy more. This is the classic theory of demand, and it works beautifully for coffee, cars, and computers. But what about health? Can you “buy” health? If the price of a doctor’s visit goes up, do people just “demand” less health? It all gets complicated, and fast. The truth is, health defies the simple rules of traditional demand theory.
Trying to build a standard demand function for health is like trying to nail jelly to a wall. The core problem is that health isn’t a single “thing” you can buy off a shelf. Let’s look at why it’s so different.
- It’s intangible: You can’t hold “health.” You can buy things that contribute to it, like medicine, a gym membership, or healthy food, but the “health” itself is a state of being.
- It’s personal and variable: If two people buy the same car, they get the same car. If two people with a cough take the same medicine, one might be cured instantly while the other gets no relief. The *outcome* of health “purchases” is incredibly variable.
- You are the factory: This is the big one. You are both the consumer *and* the producer of your own health. A doctor can give you advice, but *you* have to follow it. You produce your health by sleeping, eating well, and exercising. No one else can do it for you.
Because of these unique features, economists needed a new way of thinking. Two economists, Gary Becker and Michael Grossman, provided the frameworks that revolutionized how we understand the “demand” for health.
Table of Contents
- A new way of thinking: The household as a ‘health factory’
- Becker’s theory of consumer behaviour
- The Grossman model: Thinking of health as an investment
- Health as a capital stock
- The inevitable decline: Depreciation
- Fighting back: Gross investment in health
- Putting it all together: Why this matters for behaviour
- The lifetime balancing act
- Explaining education and health
- Explaining health demand over a lifetime
A new way of thinking: The household as a ‘health factory’
Before we can understand the demand for health, we have to understand how economists think about households. For a long time, economics focused on firms (producers) and individuals (consumers). Then, economist Gary Becker came along and changed everything.
Becker argued that a household isn’t just a place where people consume things; it’s a small factory. Households “produce” commodities that they value, like a clean house, a home-cooked meal, and yes, “health.”
Becker’s theory of consumer behaviour
Becker’s big idea was that people don’t just demand market goods (like eggs, flour, and sugar) for their own sake. They demand those goods as inputs to produce something else they *really* want (a birthday cake).
Think about it: You don’t “demand” a doctor’s visit. You demand “to feel better.” The doctor’s visit, the medicine, and the time you take off work are all inputs into your household’s “health factory.” The output you want is “a healthy day.”
This means the demand for market goods-like medical services-is a derived demand. It’s derived from your fundamental demand for the final commodity: health itself.
This model also brilliantly incorporated a resource that economists had often ignored: time. The “full price” of that birthday cake isn’t just the cost of the ingredients; it’s the cost of the ingredients *plus* the value of the time you spent baking it. For health, the “full price” of getting better isn’t just the hospital bill; it’s the bill *plus* the time you spent in the waiting room, the time spent resting in bed, and the time spent exercising.
The Grossman model: Thinking of health as an investment
Building on Becker’s foundation, economist Michael Grossman developed what is now the most famous model in health economics. He asked a simple but profound question: Is health something you *consume* (like a meal, it’s gone after you use it) or something you *own* (like a house, it provides value over time)?
Grossman’s answer was that health is a durable capital stock. This is the single most important concept for understanding the demand for health.
Let’s break down that academic-sounding phrase with an analogy. Think of your health just like a car.
Health as a capital stock
A car is a “capital stock.” You own it. It provides you with a service over time: transportation. You don’t “consume” the car all at once. Every day, it gives you a flow of “transportation services.”
Your “health stock” is the same. It’s a capital good you “own.” It provides you with a flow of services every day: “healthy time” or “healthy days.” This healthy time is what you *really* want. It allows you to do everything else in life: go to work and earn money, enjoy hobbies, and spend time with family.
The inevitable decline: Depreciation
Just like your car, your health stock is subject to wear and tear. In economics, this is called depreciation. Every year, your car gets a little rustier and runs a little less smoothly. Every year, your health stock naturally depreciates-this is what we call aging. As we get older, this rate of depreciation often gets faster.
Fighting back: Gross investment in health
What do you do when your car breaks down? You take it to the mechanic. You invest in it-you get an oil change, new tires, and a tune-up. This is a “gross investment.”
You do the same for your health stock. When you feel it depreciating (you get sick, or just feel older), you make a gross investment in your health. This investment can be:
- Medical care: Going to the doctor, buying medicine.
- Lifestyle choices: Exercising, eating a good diet, getting enough sleep.
- Other inputs: Good housing, a safe environment.
Your “net investment” is simply your gross investment minus depreciation. If your investment is greater than depreciation, your health stock increases. If it’s less, your health stock falls.
Putting it all together: Why this matters for behaviour
This “health capital” model brilliantly explains real-world behaviour that traditional demand theory can’t.
The lifetime balancing act
Grossman’s model assumes that we are rational individuals trying to maximize our utility (or happiness) over our entire lifetime. We have limited resources: time and money. We have to decide how to allocate them.
Every day, we face a choice. We can use our time and money to make “health investments” (like going for a run or buying vegetables) or we can use them to produce other “commodities” (like watching a movie or going on vacation).
The cost of investing in health is the “opportunity cost”-the time and money you *could* have spent on that vacation.
The benefit of investing in health is a larger health stock, which gives you more “healthy days” in the future to work, earn, and enjoy other things.
This model views health as both a consumption good (it feels good to be healthy right now) and an investment good (it allows you to be productive and healthy tomorrow). This dual nature is key.
Explaining education and health
The Grossman model makes a powerful prediction: More educated people will demand more health. Why? Not necessarily because they have more money. It’s because education makes them more *efficient* producers of health.
An educated person might know *how* to use health inputs better. They might understand a doctor’s instructions more clearly, know the value of nutrition and exercise, and be better at avoiding risks. They can produce *more* health from the *same* amount of inputs (time and money), effectively lowering the “price” of health for them.
Explaining health demand over a lifetime
Why does demand for medical care skyrocket when people get old?
Traditional theory would struggle. But in the Grossman model, the answer is clear. As we age, the rate of depreciation on our health stock increases dramatically. Our “health car” is rusting faster.
Therefore, just to *maintain* the same level of health stock (to keep the car running), we need to make massive “gross investments” in the form of medical care. We’re not trying to get *more* health; we’re spending a fortune just to slow down the decline.
This framework, viewing health as a self-produced, durable investment, is the foundation of all modern health economics. It separates the “demand for health” (a capital stock) from the “demand for medical care” (an input to protect that stock). It reminds us that health is not something we buy, but something we build, maintain, and invest in over a lifetime.
What do you think? How do you personally view your ‘health stock’? Do you see your daily choices about food and exercise more as consumption (feeling good now) or as an investment (building a foundation for later)?
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